diff options
Diffstat (limited to 'drivers/gpu/drm/drm_irq.c')
| -rw-r--r-- | drivers/gpu/drm/drm_irq.c | 1417 |
1 files changed, 1417 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c new file mode 100644 index 0000000..f92da0a --- /dev/null +++ b/drivers/gpu/drm/drm_irq.c @@ -0,0 +1,1417 @@ +/** + * \file drm_irq.c + * IRQ support + * + * \author Rickard E. (Rik) Faith <faith@valinux.com> + * \author Gareth Hughes <gareth@valinux.com> + */ + +/* + * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com + * + * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas. + * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California. + * All Rights Reserved. + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice (including the next + * paragraph) shall be included in all copies or substantial portions of the + * Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + */ + +#include <drm/drmP.h> +#include "drm_trace.h" + +#include <linux/interrupt.h> /* For task queue support */ +#include <linux/slab.h> + +#include <linux/vgaarb.h> +#include <linux/export.h> + +/* Access macro for slots in vblank timestamp ringbuffer. */ +#define vblanktimestamp(dev, crtc, count) ( \ + (dev)->_vblank_time[(crtc) * DRM_VBLANKTIME_RBSIZE + \ + ((count) % DRM_VBLANKTIME_RBSIZE)]) + +/* Retry timestamp calculation up to 3 times to satisfy + * drm_timestamp_precision before giving up. + */ +#define DRM_TIMESTAMP_MAXRETRIES 3 + +/* Threshold in nanoseconds for detection of redundant + * vblank irq in drm_handle_vblank(). 1 msec should be ok. + */ +#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000 + +/** + * Get interrupt from bus id. + * + * \param inode device inode. + * \param file_priv DRM file private. + * \param cmd command. + * \param arg user argument, pointing to a drm_irq_busid structure. + * \return zero on success or a negative number on failure. + * + * Finds the PCI device with the specified bus id and gets its IRQ number. + * This IOCTL is deprecated, and will now return EINVAL for any busid not equal + * to that of the device that this DRM instance attached to. + */ +int drm_irq_by_busid(struct drm_device *dev, void *data, + struct drm_file *file_priv) +{ + struct drm_irq_busid *p = data; + + if (!dev->driver->bus->irq_by_busid) + return -EINVAL; + + if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) + return -EINVAL; + + return dev->driver->bus->irq_by_busid(dev, p); +} + +/* + * Clear vblank timestamp buffer for a crtc. + */ +static void clear_vblank_timestamps(struct drm_device *dev, int crtc) +{ + memset(&dev->_vblank_time[crtc * DRM_VBLANKTIME_RBSIZE], 0, + DRM_VBLANKTIME_RBSIZE * sizeof(struct timeval)); +} + +/* + * Disable vblank irq's on crtc, make sure that last vblank count + * of hardware and corresponding consistent software vblank counter + * are preserved, even if there are any spurious vblank irq's after + * disable. + */ +static void vblank_disable_and_save(struct drm_device *dev, int crtc) +{ + unsigned long irqflags; + u32 vblcount; + s64 diff_ns; + int vblrc; + struct timeval tvblank; + int count = DRM_TIMESTAMP_MAXRETRIES; + + /* Prevent vblank irq processing while disabling vblank irqs, + * so no updates of timestamps or count can happen after we've + * disabled. Needed to prevent races in case of delayed irq's. + */ + spin_lock_irqsave(&dev->vblank_time_lock, irqflags); + + dev->driver->disable_vblank(dev, crtc); + dev->vblank_enabled[crtc] = 0; + + /* No further vblank irq's will be processed after + * this point. Get current hardware vblank count and + * vblank timestamp, repeat until they are consistent. + * + * FIXME: There is still a race condition here and in + * drm_update_vblank_count() which can cause off-by-one + * reinitialization of software vblank counter. If gpu + * vblank counter doesn't increment exactly at the leading + * edge of a vblank interval, then we can lose 1 count if + * we happen to execute between start of vblank and the + * delayed gpu counter increment. + */ + do { + dev->last_vblank[crtc] = dev->driver->get_vblank_counter(dev, crtc); + vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0); + } while (dev->last_vblank[crtc] != dev->driver->get_vblank_counter(dev, crtc) && (--count) && vblrc); + + if (!count) + vblrc = 0; + + /* Compute time difference to stored timestamp of last vblank + * as updated by last invocation of drm_handle_vblank() in vblank irq. + */ + vblcount = atomic_read(&dev->_vblank_count[crtc]); + diff_ns = timeval_to_ns(&tvblank) - + timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount)); + + /* If there is at least 1 msec difference between the last stored + * timestamp and tvblank, then we are currently executing our + * disable inside a new vblank interval, the tvblank timestamp + * corresponds to this new vblank interval and the irq handler + * for this vblank didn't run yet and won't run due to our disable. + * Therefore we need to do the job of drm_handle_vblank() and + * increment the vblank counter by one to account for this vblank. + * + * Skip this step if there isn't any high precision timestamp + * available. In that case we can't account for this and just + * hope for the best. + */ + if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) { + atomic_inc(&dev->_vblank_count[crtc]); + smp_mb__after_atomic_inc(); + } + + /* Invalidate all timestamps while vblank irq's are off. */ + clear_vblank_timestamps(dev, crtc); + + spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); +} + +static void vblank_disable_fn(unsigned long arg) +{ + struct drm_device *dev = (struct drm_device *)arg; + unsigned long irqflags; + int i; + + if (!dev->vblank_disable_allowed) + return; + + for (i = 0; i < dev->num_crtcs; i++) { + spin_lock_irqsave(&dev->vbl_lock, irqflags); + if (atomic_read(&dev->vblank_refcount[i]) == 0 && + dev->vblank_enabled[i]) { + DRM_DEBUG("disabling vblank on crtc %d\n", i); + vblank_disable_and_save(dev, i); + } + spin_unlock_irqrestore(&dev->vbl_lock, irqflags); + } +} + +void drm_vblank_cleanup(struct drm_device *dev) +{ + /* Bail if the driver didn't call drm_vblank_init() */ + if (dev->num_crtcs == 0) + return; + + del_timer_sync(&dev->vblank_disable_timer); + + vblank_disable_fn((unsigned long)dev); + + kfree(dev->vbl_queue); + kfree(dev->_vblank_count); + kfree(dev->vblank_refcount); + kfree(dev->vblank_enabled); + kfree(dev->last_vblank); + kfree(dev->last_vblank_wait); + kfree(dev->vblank_inmodeset); + kfree(dev->_vblank_time); + + dev->num_crtcs = 0; +} +EXPORT_SYMBOL(drm_vblank_cleanup); + +int drm_vblank_init(struct drm_device *dev, int num_crtcs) +{ + int i, ret = -ENOMEM; + + setup_timer(&dev->vblank_disable_timer, vblank_disable_fn, + (unsigned long)dev); + spin_lock_init(&dev->vbl_lock); + spin_lock_init(&dev->vblank_time_lock); + + dev->num_crtcs = num_crtcs; + + dev->vbl_queue = kmalloc(sizeof(wait_queue_head_t) * num_crtcs, + GFP_KERNEL); + if (!dev->vbl_queue) + goto err; + + dev->_vblank_count = kmalloc(sizeof(atomic_t) * num_crtcs, GFP_KERNEL); + if (!dev->_vblank_count) + goto err; + + dev->vblank_refcount = kmalloc(sizeof(atomic_t) * num_crtcs, + GFP_KERNEL); + if (!dev->vblank_refcount) + goto err; + + dev->vblank_enabled = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL); + if (!dev->vblank_enabled) + goto err; + + dev->last_vblank = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL); + if (!dev->last_vblank) + goto err; + + dev->last_vblank_wait = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL); + if (!dev->last_vblank_wait) + goto err; + + dev->vblank_inmodeset = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL); + if (!dev->vblank_inmodeset) + goto err; + + dev->_vblank_time = kcalloc(num_crtcs * DRM_VBLANKTIME_RBSIZE, + sizeof(struct timeval), GFP_KERNEL); + if (!dev->_vblank_time) + goto err; + + DRM_INFO("Supports vblank timestamp caching Rev 1 (10.10.2010).\n"); + + /* Driver specific high-precision vblank timestamping supported? */ + if (dev->driver->get_vblank_timestamp) + DRM_INFO("Driver supports precise vblank timestamp query.\n"); + else + DRM_INFO("No driver support for vblank timestamp query.\n"); + + /* Zero per-crtc vblank stuff */ + for (i = 0; i < num_crtcs; i++) { + init_waitqueue_head(&dev->vbl_queue[i]); + atomic_set(&dev->_vblank_count[i], 0); + atomic_set(&dev->vblank_refcount[i], 0); + } + + dev->vblank_disable_allowed = 0; + return 0; + +err: + drm_vblank_cleanup(dev); + return ret; +} +EXPORT_SYMBOL(drm_vblank_init); + +static void drm_irq_vgaarb_nokms(void *cookie, bool state) +{ + struct drm_device *dev = cookie; + + if (dev->driver->vgaarb_irq) { + dev->driver->vgaarb_irq(dev, state); + return; + } + + if (!dev->irq_enabled) + return; + + if (state) { + if (dev->driver->irq_uninstall) + dev->driver->irq_uninstall(dev); + } else { + if (dev->driver->irq_preinstall) + dev->driver->irq_preinstall(dev); + if (dev->driver->irq_postinstall) + dev->driver->irq_postinstall(dev); + } +} + +/** + * Install IRQ handler. + * + * \param dev DRM device. + * + * Initializes the IRQ related data. Installs the handler, calling the driver + * \c irq_preinstall() and \c irq_postinstall() functions + * before and after the installation. + */ +int drm_irq_install(struct drm_device *dev) +{ + int ret; + unsigned long sh_flags = 0; + char *irqname; + + if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) + return -EINVAL; + + if (drm_dev_to_irq(dev) == 0) + return -EINVAL; + + mutex_lock(&dev->struct_mutex); + + /* Driver must have been initialized */ + if (!dev->dev_private) { + mutex_unlock(&dev->struct_mutex); + return -EINVAL; + } + + if (dev->irq_enabled) { + mutex_unlock(&dev->struct_mutex); + return -EBUSY; + } + dev->irq_enabled = 1; + mutex_unlock(&dev->struct_mutex); + + DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev)); + + /* Before installing handler */ + if (dev->driver->irq_preinstall) + dev->driver->irq_preinstall(dev); + + /* Install handler */ + if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED)) + sh_flags = IRQF_SHARED; + + if (dev->devname) + irqname = dev->devname; + else + irqname = dev->driver->name; + + ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler, + sh_flags, irqname, dev); + + if (ret < 0) { + mutex_lock(&dev->struct_mutex); + dev->irq_enabled = 0; + mutex_unlock(&dev->struct_mutex); + return ret; + } + + if (!drm_core_check_feature(dev, DRIVER_MODESET)) + vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL); + + /* After installing handler */ + if (dev->driver->irq_postinstall) + ret = dev->driver->irq_postinstall(dev); + + if (ret < 0) { + mutex_lock(&dev->struct_mutex); + dev->irq_enabled = 0; + mutex_unlock(&dev->struct_mutex); + if (!drm_core_check_feature(dev, DRIVER_MODESET)) + vga_client_register(dev->pdev, NULL, NULL, NULL); + free_irq(drm_dev_to_irq(dev), dev); + } + + return ret; +} +EXPORT_SYMBOL(drm_irq_install); + +/** + * Uninstall the IRQ handler. + * + * \param dev DRM device. + * + * Calls the driver's \c irq_uninstall() function, and stops the irq. + */ +int drm_irq_uninstall(struct drm_device *dev) +{ + unsigned long irqflags; + int irq_enabled, i; + + if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) + return -EINVAL; + + mutex_lock(&dev->struct_mutex); + irq_enabled = dev->irq_enabled; + dev->irq_enabled = 0; + mutex_unlock(&dev->struct_mutex); + + /* + * Wake up any waiters so they don't hang. + */ + if (dev->num_crtcs) { + spin_lock_irqsave(&dev->vbl_lock, irqflags); + for (i = 0; i < dev->num_crtcs; i++) { + DRM_WAKEUP(&dev->vbl_queue[i]); + dev->vblank_enabled[i] = 0; + dev->last_vblank[i] = + dev->driver->get_vblank_counter(dev, i); + } + spin_unlock_irqrestore(&dev->vbl_lock, irqflags); + } + + if (!irq_enabled) + return -EINVAL; + + DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev)); + + if (!drm_core_check_feature(dev, DRIVER_MODESET)) + vga_client_register(dev->pdev, NULL, NULL, NULL); + + if (dev->driver->irq_uninstall) + dev->driver->irq_uninstall(dev); + + free_irq(drm_dev_to_irq(dev), dev); + + return 0; +} +EXPORT_SYMBOL(drm_irq_uninstall); + +/** + * IRQ control ioctl. + * + * \param inode device inode. + * \param file_priv DRM file private. + * \param cmd command. + * \param arg user argument, pointing to a drm_control structure. + * \return zero on success or a negative number on failure. + * + * Calls irq_install() or irq_uninstall() according to \p arg. + */ +int drm_control(struct drm_device *dev, void *data, + struct drm_file *file_priv) +{ + struct drm_control *ctl = data; + + /* if we haven't irq we fallback for compatibility reasons - + * this used to be a separate function in drm_dma.h + */ + + + switch (ctl->func) { + case DRM_INST_HANDLER: + if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) + return 0; + if (drm_core_check_feature(dev, DRIVER_MODESET)) + return 0; + if (dev->if_version < DRM_IF_VERSION(1, 2) && + ctl->irq != drm_dev_to_irq(dev)) + return -EINVAL; + return drm_irq_install(dev); + case DRM_UNINST_HANDLER: + if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) + return 0; + if (drm_core_check_feature(dev, DRIVER_MODESET)) + return 0; + return drm_irq_uninstall(dev); + default: + return -EINVAL; + } +} + +/** + * drm_calc_timestamping_constants - Calculate and + * store various constants which are later needed by + * vblank and swap-completion timestamping, e.g, by + * drm_calc_vbltimestamp_from_scanoutpos(). + * They are derived from crtc's true scanout timing, + * so they take things like panel scaling or other + * adjustments into account. + * + * @crtc drm_crtc whose timestamp constants should be updated. + * + */ +void drm_calc_timestamping_constants(struct drm_crtc *crtc) +{ + s64 linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0; + u64 dotclock; + + /* Dot clock in Hz: */ + dotclock = (u64) crtc->hwmode.clock * 1000; + + /* Fields of interlaced scanout modes are only halve a frame duration. + * Double the dotclock to get halve the frame-/line-/pixelduration. + */ + if (crtc->hwmode.flags & DRM_MODE_FLAG_INTERLACE) + dotclock *= 2; + + /* Valid dotclock? */ + if (dotclock > 0) { + int frame_size; + /* Convert scanline length in pixels and video dot clock to + * line duration, frame duration and pixel duration in + * nanoseconds: + */ + pixeldur_ns = (s64) div64_u64(1000000000, dotclock); + linedur_ns = (s64) div64_u64(((u64) crtc->hwmode.crtc_htotal * + 1000000000), dotclock); + frame_size = crtc->hwmode.crtc_htotal * + crtc->hwmode.crtc_vtotal; + framedur_ns = (s64) div64_u64((u64) frame_size * 1000000000, + dotclock); + } else + DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n", + crtc->base.id); + + crtc->pixeldur_ns = pixeldur_ns; + crtc->linedur_ns = linedur_ns; + crtc->framedur_ns = framedur_ns; + + DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n", + crtc->base.id, crtc->hwmode.crtc_htotal, + crtc->hwmode.crtc_vtotal, crtc->hwmode.crtc_vdisplay); + DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n", + crtc->base.id, (int) dotclock/1000, (int) framedur_ns, + (int) linedur_ns, (int) pixeldur_ns); +} +EXPORT_SYMBOL(drm_calc_timestamping_constants); + +/** + * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms + * drivers. Implements calculation of exact vblank timestamps from + * given drm_display_mode timings and current video scanout position + * of a crtc. This can be called from within get_vblank_timestamp() + * implementation of a kms driver to implement the actual timestamping. + * + * Should return timestamps conforming to the OML_sync_control OpenML + * extension specification. The timestamp corresponds to the end of + * the vblank interval, aka start of scanout of topmost-leftmost display + * pixel in the following video frame. + * + * Requires support for optional dev->driver->get_scanout_position() + * in kms driver, plus a bit of setup code to provide a drm_display_mode + * that corresponds to the true scanout timing. + * + * The current implementation only handles standard video modes. It + * returns as no operation if a doublescan or interlaced video mode is + * active. Higher level code is expected to handle this. + * + * @dev: DRM device. + * @crtc: Which crtc's vblank timestamp to retrieve. + * @max_error: Desired maximum allowable error in timestamps (nanosecs). + * On return contains true maximum error of timestamp. + * @vblank_time: Pointer to struct timeval which should receive the timestamp. + * @flags: Flags to pass to driver: + * 0 = Default. + * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler. + * @refcrtc: drm_crtc* of crtc which defines scanout timing. + * + * Returns negative value on error, failure or if not supported in current + * video mode: + * + * -EINVAL - Invalid crtc. + * -EAGAIN - Temporary unavailable, e.g., called before initial modeset. + * -ENOTSUPP - Function not supported in current display mode. + * -EIO - Failed, e.g., due to failed scanout position query. + * + * Returns or'ed positive status flags on success: + * + * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping. + * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval. + * + */ +int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc, + int *max_error, + struct timeval *vblank_time, + unsigned flags, + struct drm_crtc *refcrtc) +{ + ktime_t stime, etime, mono_time_offset; + struct timeval tv_etime; + struct drm_display_mode *mode; + int vbl_status, vtotal, vdisplay; + int vpos, hpos, i; + s64 framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns; + bool invbl; + + if (crtc < 0 || crtc >= dev->num_crtcs) { + DRM_ERROR("Invalid crtc %d\n", crtc); + return -EINVAL; + } + + /* Scanout position query not supported? Should not happen. */ + if (!dev->driver->get_scanout_position) { + DRM_ERROR("Called from driver w/o get_scanout_position()!?\n"); + return -EIO; + } + + mode = &refcrtc->hwmode; + vtotal = mode->crtc_vtotal; + vdisplay = mode->crtc_vdisplay; + + /* Durations of frames, lines, pixels in nanoseconds. */ + framedur_ns = refcrtc->framedur_ns; + linedur_ns = refcrtc->linedur_ns; + pixeldur_ns = refcrtc->pixeldur_ns; + + /* If mode timing undefined, just return as no-op: + * Happens during initial modesetting of a crtc. + */ + if (vtotal <= 0 || vdisplay <= 0 || framedur_ns == 0) { + DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc); + return -EAGAIN; + } + + /* Get current scanout position with system timestamp. + * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times + * if single query takes longer than max_error nanoseconds. + * + * This guarantees a tight bound on maximum error if + * code gets preempted or delayed for some reason. + */ + for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) { + /* Disable preemption to make it very likely to + * succeed in the first iteration even on PREEMPT_RT kernel. + */ + preempt_disable(); + + /* Get system timestamp before query. */ + stime = ktime_get(); + + /* Get vertical and horizontal scanout pos. vpos, hpos. */ + vbl_status = dev->driver->get_scanout_position(dev, crtc, &vpos, &hpos); + + /* Get system timestamp after query. */ + etime = ktime_get(); + if (!drm_timestamp_monotonic) + mono_time_offset = ktime_get_monotonic_offset(); + + preempt_enable(); + + /* Return as no-op if scanout query unsupported or failed. */ + if (!(vbl_status & DRM_SCANOUTPOS_VALID)) { + DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n", + crtc, vbl_status); + return -EIO; + } + + duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime); + + /* Accept result with < max_error nsecs timing uncertainty. */ + if (duration_ns <= (s64) *max_error) + break; + } + + /* Noisy system timing? */ + if (i == DRM_TIMESTAMP_MAXRETRIES) { + DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n", + crtc, (int) duration_ns/1000, *max_error/1000, i); + } + + /* Return upper bound of timestamp precision error. */ + *max_error = (int) duration_ns; + + /* Check if in vblank area: + * vpos is >=0 in video scanout area, but negative + * within vblank area, counting down the number of lines until + * start of scanout. + */ + invbl = vbl_status & DRM_SCANOUTPOS_INVBL; + + /* Convert scanout position into elapsed time at raw_time query + * since start of scanout at first display scanline. delta_ns + * can be negative if start of scanout hasn't happened yet. + */ + delta_ns = (s64) vpos * linedur_ns + (s64) hpos * pixeldur_ns; + + /* Is vpos outside nominal vblank area, but less than + * 1/100 of a frame height away from start of vblank? + * If so, assume this isn't a massively delayed vblank + * interrupt, but a vblank interrupt that fired a few + * microseconds before true start of vblank. Compensate + * by adding a full frame duration to the final timestamp. + * Happens, e.g., on ATI R500, R600. + * + * We only do this if DRM_CALLED_FROM_VBLIRQ. + */ + if ((flags & DRM_CALLED_FROM_VBLIRQ) && !invbl && + ((vdisplay - vpos) < vtotal / 100)) { + delta_ns = delta_ns - framedur_ns; + + /* Signal this correction as "applied". */ + vbl_status |= 0x8; + } + + if (!drm_timestamp_monotonic) + etime = ktime_sub(etime, mono_time_offset); + + /* save this only for debugging purposes */ + tv_etime = ktime_to_timeval(etime); + /* Subtract time delta from raw timestamp to get final + * vblank_time timestamp for end of vblank. + */ + if (delta_ns < 0) + etime = ktime_add_ns(etime, -delta_ns); + else + etime = ktime_sub_ns(etime, delta_ns); + *vblank_time = ktime_to_timeval(etime); + + DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n", + crtc, (int)vbl_status, hpos, vpos, + (long)tv_etime.tv_sec, (long)tv_etime.tv_usec, + (long)vblank_time->tv_sec, (long)vblank_time->tv_usec, + (int)duration_ns/1000, i); + + vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD; + if (invbl) + vbl_status |= DRM_VBLANKTIME_INVBL; + + return vbl_status; +} +EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos); + +static struct timeval get_drm_timestamp(void) +{ + ktime_t now; + + now = ktime_get(); + if (!drm_timestamp_monotonic) + now = ktime_sub(now, ktime_get_monotonic_offset()); + + return ktime_to_timeval(now); +} + +/** + * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent + * vblank interval. + * + * @dev: DRM device + * @crtc: which crtc's vblank timestamp to retrieve + * @tvblank: Pointer to target struct timeval which should receive the timestamp + * @flags: Flags to pass to driver: + * 0 = Default. + * DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler. + * + * Fetches the system timestamp corresponding to the time of the most recent + * vblank interval on specified crtc. May call into kms-driver to + * compute the timestamp with a high-precision GPU specific method. + * + * Returns zero if timestamp originates from uncorrected do_gettimeofday() + * call, i.e., it isn't very precisely locked to the true vblank. + * + * Returns non-zero if timestamp is considered to be very precise. + */ +u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc, + struct timeval *tvblank, unsigned flags) +{ + int ret; + + /* Define requested maximum error on timestamps (nanoseconds). */ + int max_error = (int) drm_timestamp_precision * 1000; + + /* Query driver if possible and precision timestamping enabled. */ + if (dev->driver->get_vblank_timestamp && (max_error > 0)) { + ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error, + tvblank, flags); + if (ret > 0) + return (u32) ret; + } + + /* GPU high precision timestamp query unsupported or failed. + * Return current monotonic/gettimeofday timestamp as best estimate. + */ + *tvblank = get_drm_timestamp(); + + return 0; +} +EXPORT_SYMBOL(drm_get_last_vbltimestamp); + +/** + * drm_vblank_count - retrieve "cooked" vblank counter value + * @dev: DRM device + * @crtc: which counter to retrieve + * + * Fetches the "cooked" vblank count value that represents the number of + * vblank events since the system was booted, including lost events due to + * modesetting activity. + */ +u32 drm_vblank_count(struct drm_device *dev, int crtc) +{ + return atomic_read(&dev->_vblank_count[crtc]); +} +EXPORT_SYMBOL(drm_vblank_count); + +/** + * drm_vblank_count_and_time - retrieve "cooked" vblank counter value + * and the system timestamp corresponding to that vblank counter value. + * + * @dev: DRM device + * @crtc: which counter to retrieve + * @vblanktime: Pointer to struct timeval to receive the vblank timestamp. + * + * Fetches the "cooked" vblank count value that represents the number of + * vblank events since the system was booted, including lost events due to + * modesetting activity. Returns corresponding system timestamp of the time + * of the vblank interval that corresponds to the current value vblank counter + * value. + */ +u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc, + struct timeval *vblanktime) +{ + u32 cur_vblank; + + /* Read timestamp from slot of _vblank_time ringbuffer + * that corresponds to current vblank count. Retry if + * count has incremented during readout. This works like + * a seqlock. + */ + do { + cur_vblank = atomic_read(&dev->_vblank_count[crtc]); + *vblanktime = vblanktimestamp(dev, crtc, cur_vblank); + smp_rmb(); + } while (cur_vblank != atomic_read(&dev->_vblank_count[crtc])); + + return cur_vblank; +} +EXPORT_SYMBOL(drm_vblank_count_and_time); + +static void send_vblank_event(struct drm_device *dev, + struct drm_pending_vblank_event *e, + unsigned long seq, struct timeval *now) +{ + WARN_ON_SMP(!spin_is_locked(&dev->event_lock)); + e->event.sequence = seq; + e->event.tv_sec = now->tv_sec; + e->event.tv_usec = now->tv_usec; + + list_add_tail(&e->base.link, + &e->base.file_priv->event_list); + wake_up_interruptible(&e->base.file_priv->event_wait); + trace_drm_vblank_event_delivered(e->base.pid, e->pipe, + e->event.sequence); +} + +/** + * drm_send_vblank_event - helper to send vblank event after pageflip + * @dev: DRM device + * @crtc: CRTC in question + * @e: the event to send + * + * Updates sequence # and timestamp on event, and sends it to userspace. + * Caller must hold event lock. + */ +void drm_send_vblank_event(struct drm_device *dev, int crtc, + struct drm_pending_vblank_event *e) +{ + struct timeval now; + unsigned int seq; + if (crtc >= 0) { + seq = drm_vblank_count_and_time(dev, crtc, &now); + } else { + seq = 0; + + now = get_drm_timestamp(); + } + e->pipe = crtc; + send_vblank_event(dev, e, seq, &now); +} +EXPORT_SYMBOL(drm_send_vblank_event); + +/** + * drm_update_vblank_count - update the master vblank counter + * @dev: DRM device + * @crtc: counter to update + * + * Call back into the driver to update the appropriate vblank counter + * (specified by @crtc). Deal with wraparound, if it occurred, and + * update the last read value so we can deal with wraparound on the next + * call if necessary. + * + * Only necessary when going from off->on, to account for frames we + * didn't get an interrupt for. + * + * Note: caller must hold dev->vbl_lock since this reads & writes + * device vblank fields. + */ +static void drm_update_vblank_count(struct drm_device *dev, int crtc) +{ + u32 cur_vblank, diff, tslot, rc; + struct timeval t_vblank; + + /* + * Interrupts were disabled prior to this call, so deal with counter + * wrap if needed. + * NOTE! It's possible we lost a full dev->max_vblank_count events + * here if the register is small or we had vblank interrupts off for + * a long time. + * + * We repeat the hardware vblank counter & timestamp query until + * we get consistent results. This to prevent races between gpu + * updating its hardware counter while we are retrieving the + * corresponding vblank timestamp. + */ + do { + cur_vblank = dev->driver->get_vblank_counter(dev, crtc); + rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0); + } while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc)); + + /* Deal with counter wrap */ + diff = cur_vblank - dev->last_vblank[crtc]; + if (cur_vblank < dev->last_vblank[crtc]) { + diff += dev->max_vblank_count; + + DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n", + crtc, dev->last_vblank[crtc], cur_vblank, diff); + } + + DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n", + crtc, diff); + + /* Reinitialize corresponding vblank timestamp if high-precision query + * available. Skip this step if query unsupported or failed. Will + * reinitialize delayed at next vblank interrupt in that case. + */ + if (rc) { + tslot = atomic_read(&dev->_vblank_count[crtc]) + diff; + vblanktimestamp(dev, crtc, tslot) = t_vblank; + } + + smp_mb__before_atomic_inc(); + atomic_add(diff, &dev->_vblank_count[crtc]); + smp_mb__after_atomic_inc(); +} + +/** + * drm_vblank_get - get a reference count on vblank events + * @dev: DRM device + * @crtc: which CRTC to own + * + * Acquire a reference count on vblank events to avoid having them disabled + * while in use. + * + * RETURNS + * Zero on success, nonzero on failure. + */ +int drm_vblank_get(struct drm_device *dev, int crtc) +{ + unsigned long irqflags, irqflags2; + int ret = 0; + + spin_lock_irqsave(&dev->vbl_lock, irqflags); + /* Going from 0->1 means we have to enable interrupts again */ + if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1) { + spin_lock_irqsave(&dev->vblank_time_lock, irqflags2); + if (!dev->vblank_enabled[crtc]) { + /* Enable vblank irqs under vblank_time_lock protection. + * All vblank count & timestamp updates are held off + * until we are done reinitializing master counter and + * timestamps. Filtercode in drm_handle_vblank() will + * prevent double-accounting of same vblank interval. + */ + ret = dev->driver->enable_vblank(dev, crtc); + DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n", + crtc, ret); + if (ret) + atomic_dec(&dev->vblank_refcount[crtc]); + else { + dev->vblank_enabled[crtc] = 1; + drm_update_vblank_count(dev, crtc); + } + } + spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags2); + } else { + if (!dev->vblank_enabled[crtc]) { + atomic_dec(&dev->vblank_refcount[crtc]); + ret = -EINVAL; + } + } + spin_unlock_irqrestore(&dev->vbl_lock, irqflags); + + return ret; +} +EXPORT_SYMBOL(drm_vblank_get); + +/** + * drm_vblank_put - give up ownership of vblank events + * @dev: DRM device + * @crtc: which counter to give up + * + * Release ownership of a given vblank counter, turning off interrupts + * if possible. Disable interrupts after drm_vblank_offdelay milliseconds. + */ +void drm_vblank_put(struct drm_device *dev, int crtc) +{ + BUG_ON(atomic_read(&dev->vblank_refcount[crtc]) == 0); + + /* Last user schedules interrupt disable */ + if (atomic_dec_and_test(&dev->vblank_refcount[crtc]) && + (drm_vblank_offdelay > 0)) + mod_timer(&dev->vblank_disable_timer, + jiffies + ((drm_vblank_offdelay * DRM_HZ)/1000)); +} +EXPORT_SYMBOL(drm_vblank_put); + +/** + * drm_vblank_off - disable vblank events on a CRTC + * @dev: DRM device + * @crtc: CRTC in question + * + * Caller must hold event lock. + */ +void drm_vblank_off(struct drm_device *dev, int crtc) +{ + struct drm_pending_vblank_event *e, *t; + struct timeval now; + unsigned long irqflags; + unsigned int seq; + + spin_lock_irqsave(&dev->vbl_lock, irqflags); + vblank_disable_and_save(dev, crtc); + DRM_WAKEUP(&dev->vbl_queue[crtc]); + + /* Send any queued vblank events, lest the natives grow disquiet */ + seq = drm_vblank_count_and_time(dev, crtc, &now); + + spin_lock(&dev->event_lock); + list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) { + if (e->pipe != crtc) + continue; + DRM_DEBUG("Sending premature vblank event on disable: \ + wanted %d, current %d\n", + e->event.sequence, seq); + list_del(&e->base.link); + drm_vblank_put(dev, e->pipe); + send_vblank_event(dev, e, seq, &now); + } + spin_unlock(&dev->event_lock); + + spin_unlock_irqrestore(&dev->vbl_lock, irqflags); +} +EXPORT_SYMBOL(drm_vblank_off); + +/** + * drm_vblank_pre_modeset - account for vblanks across mode sets + * @dev: DRM device + * @crtc: CRTC in question + * + * Account for vblank events across mode setting events, which will likely + * reset the hardware frame counter. + */ +void drm_vblank_pre_modeset(struct drm_device *dev, int crtc) +{ + /* vblank is not initialized (IRQ not installed ?), or has been freed */ + if (!dev->num_crtcs) + return; + /* + * To avoid all the problems that might happen if interrupts + * were enabled/disabled around or between these calls, we just + * have the kernel take a reference on the CRTC (just once though + * to avoid corrupting the count if multiple, mismatch calls occur), + * so that interrupts remain enabled in the interim. + */ + if (!dev->vblank_inmodeset[crtc]) { + dev->vblank_inmodeset[crtc] = 0x1; + if (drm_vblank_get(dev, crtc) == 0) + dev->vblank_inmodeset[crtc] |= 0x2; + } +} +EXPORT_SYMBOL(drm_vblank_pre_modeset); + +void drm_vblank_post_modeset(struct drm_device *dev, int crtc) +{ + unsigned long irqflags; + + /* vblank is not initialized (IRQ not installed ?), or has been freed */ + if (!dev->num_crtcs) + return; + + if (dev->vblank_inmodeset[crtc]) { + spin_lock_irqsave(&dev->vbl_lock, irqflags); + dev->vblank_disable_allowed = 1; + spin_unlock_irqrestore(&dev->vbl_lock, irqflags); + + if (dev->vblank_inmodeset[crtc] & 0x2) + drm_vblank_put(dev, crtc); + + dev->vblank_inmodeset[crtc] = 0; + } +} +EXPORT_SYMBOL(drm_vblank_post_modeset); + +/** + * drm_modeset_ctl - handle vblank event counter changes across mode switch + * @DRM_IOCTL_ARGS: standard ioctl arguments + * + * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET + * ioctls around modesetting so that any lost vblank events are accounted for. + * + * Generally the counter will reset across mode sets. If interrupts are + * enabled around this call, we don't have to do anything since the counter + * will have already been incremented. + */ +int drm_modeset_ctl(struct drm_device *dev, void *data, + struct drm_file *file_priv) +{ + struct drm_modeset_ctl *modeset = data; + unsigned int crtc; + + /* If drm_vblank_init() hasn't been called yet, just no-op */ + if (!dev->num_crtcs) + return 0; + + /* KMS drivers handle this internally */ + if (drm_core_check_feature(dev, DRIVER_MODESET)) + return 0; + + crtc = modeset->crtc; + if (crtc >= dev->num_crtcs) + return -EINVAL; + + switch (modeset->cmd) { + case _DRM_PRE_MODESET: + drm_vblank_pre_modeset(dev, crtc); + break; + case _DRM_POST_MODESET: + drm_vblank_post_modeset(dev, crtc); + break; + default: + return -EINVAL; + } + + return 0; +} + +static int drm_queue_vblank_event(struct drm_device *dev, int pipe, + union drm_wait_vblank *vblwait, + struct drm_file *file_priv) +{ + struct drm_pending_vblank_event *e; + struct timeval now; + unsigned long flags; + unsigned int seq; + int ret; + + e = kzalloc(sizeof *e, GFP_KERNEL); + if (e == NULL) { + ret = -ENOMEM; + goto err_put; + } + + e->pipe = pipe; + e->base.pid = current->pid; + e->event.base.type = DRM_EVENT_VBLANK; + e->event.base.length = sizeof e->event; + e->event.user_data = vblwait->request.signal; + e->base.event = &e->event.base; + e->base.file_priv = file_priv; + e->base.destroy = (void (*) (struct drm_pending_event *)) kfree; + + spin_lock_irqsave(&dev->event_lock, flags); + + if (file_priv->event_space < sizeof e->event) { + ret = -EBUSY; + goto err_unlock; + } + + file_priv->event_space -= sizeof e->event; + seq = drm_vblank_count_and_time(dev, pipe, &now); + + if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) && + (seq - vblwait->request.sequence) <= (1 << 23)) { + vblwait->request.sequence = seq + 1; + vblwait->reply.sequence = vblwait->request.sequence; + } + + DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n", + vblwait->request.sequence, seq, pipe); + + trace_drm_vblank_event_queued(current->pid, pipe, + vblwait->request.sequence); + + e->event.sequence = vblwait->request.sequence; + if ((seq - vblwait->request.sequence) <= (1 << 23)) { + drm_vblank_put(dev, pipe); + send_vblank_event(dev, e, seq, &now); + vblwait->reply.sequence = seq; + } else { + /* drm_handle_vblank_events will call drm_vblank_put */ + list_add_tail(&e->base.link, &dev->vblank_event_list); + vblwait->reply.sequence = vblwait->request.sequence; + } + + spin_unlock_irqrestore(&dev->event_lock, flags); + + return 0; + +err_unlock: + spin_unlock_irqrestore(&dev->event_lock, flags); + kfree(e); +err_put: + drm_vblank_put(dev, pipe); + return ret; +} + +/** + * Wait for VBLANK. + * + * \param inode device inode. + * \param file_priv DRM file private. + * \param cmd command. + * \param data user argument, pointing to a drm_wait_vblank structure. + * \return zero on success or a negative number on failure. + * + * This function enables the vblank interrupt on the pipe requested, then + * sleeps waiting for the requested sequence number to occur, and drops + * the vblank interrupt refcount afterwards. (vblank irq disable follows that + * after a timeout with no further vblank waits scheduled). + */ +int drm_wait_vblank(struct drm_device *dev, void *data, + struct drm_file *file_priv) +{ + union drm_wait_vblank *vblwait = data; + int ret; + unsigned int flags, seq, crtc, high_crtc; + + if (drm_core_check_feature(dev, DRIVER_HAVE_IRQ)) + if ((!drm_dev_to_irq(dev)) || (!dev->irq_enabled)) + return -EINVAL; + + if (vblwait->request.type & _DRM_VBLANK_SIGNAL) + return -EINVAL; + + if (vblwait->request.type & + ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | + _DRM_VBLANK_HIGH_CRTC_MASK)) { + DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n", + vblwait->request.type, + (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | + _DRM_VBLANK_HIGH_CRTC_MASK)); + return -EINVAL; + } + + flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK; + high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK); + if (high_crtc) + crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT; + else + crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0; + if (crtc >= dev->num_crtcs) + return -EINVAL; + + ret = drm_vblank_get(dev, crtc); + if (ret) { + DRM_DEBUG("failed to acquire vblank counter, %d\n", ret); + return ret; + } + seq = drm_vblank_count(dev, crtc); + + switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) { + case _DRM_VBLANK_RELATIVE: + vblwait->request.sequence += seq; + vblwait->request.type &= ~_DRM_VBLANK_RELATIVE; + case _DRM_VBLANK_ABSOLUTE: + break; + default: + ret = -EINVAL; + goto done; + } + + if (flags & _DRM_VBLANK_EVENT) { + /* must hold on to the vblank ref until the event fires + * drm_vblank_put will be called asynchronously + */ + return drm_queue_vblank_event(dev, crtc, vblwait, file_priv); + } + + if ((flags & _DRM_VBLANK_NEXTONMISS) && + (seq - vblwait->request.sequence) <= (1<<23)) { + vblwait->request.sequence = seq + 1; + } + + DRM_DEBUG("waiting on vblank count %d, crtc %d\n", + vblwait->request.sequence, crtc); + dev->last_vblank_wait[crtc] = vblwait->request.sequence; + DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ, + (((drm_vblank_count(dev, crtc) - + vblwait->request.sequence) <= (1 << 23)) || + !dev->irq_enabled)); + + if (ret != -EINTR) { + struct timeval now; + + vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now); + vblwait->reply.tval_sec = now.tv_sec; + vblwait->reply.tval_usec = now.tv_usec; + + DRM_DEBUG("returning %d to client\n", + vblwait->reply.sequence); + } else { + DRM_DEBUG("vblank wait interrupted by signal\n"); + } + +done: + drm_vblank_put(dev, crtc); + return ret; +} + +static void drm_handle_vblank_events(struct drm_device *dev, int crtc) +{ + struct drm_pending_vblank_event *e, *t; + struct timeval now; + unsigned long flags; + unsigned int seq; + + seq = drm_vblank_count_and_time(dev, crtc, &now); + + spin_lock_irqsave(&dev->event_lock, flags); + + list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) { + if (e->pipe != crtc) + continue; + if ((seq - e->event.sequence) > (1<<23)) + continue; + + DRM_DEBUG("vblank event on %d, current %d\n", + e->event.sequence, seq); + + list_del(&e->base.link); + drm_vblank_put(dev, e->pipe); + send_vblank_event(dev, e, seq, &now); + } + + spin_unlock_irqrestore(&dev->event_lock, flags); + + trace_drm_vblank_event(crtc, seq); +} + +/** + * drm_handle_vblank - handle a vblank event + * @dev: DRM device + * @crtc: where this event occurred + * + * Drivers should call this routine in their vblank interrupt handlers to + * update the vblank counter and send any signals that may be pending. + */ +bool drm_handle_vblank(struct drm_device *dev, int crtc) +{ + u32 vblcount; + s64 diff_ns; + struct timeval tvblank; + unsigned long irqflags; + + if (!dev->num_crtcs) + return false; + + /* Need timestamp lock to prevent concurrent execution with + * vblank enable/disable, as this would cause inconsistent + * or corrupted timestamps and vblank counts. + */ + spin_lock_irqsave(&dev->vblank_time_lock, irqflags); + + /* Vblank irq handling disabled. Nothing to do. */ + if (!dev->vblank_enabled[crtc]) { + spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); + return false; + } + + /* Fetch corresponding timestamp for this vblank interval from + * driver and store it in proper slot of timestamp ringbuffer. + */ + + /* Get current timestamp and count. */ + vblcount = atomic_read(&dev->_vblank_count[crtc]); + drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ); + + /* Compute time difference to timestamp of last vblank */ + diff_ns = timeval_to_ns(&tvblank) - + timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount)); + + /* Update vblank timestamp and count if at least + * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds + * difference between last stored timestamp and current + * timestamp. A smaller difference means basically + * identical timestamps. Happens if this vblank has + * been already processed and this is a redundant call, + * e.g., due to spurious vblank interrupts. We need to + * ignore those for accounting. + */ + if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) { + /* Store new timestamp in ringbuffer. */ + vblanktimestamp(dev, crtc, vblcount + 1) = tvblank; + + /* Increment cooked vblank count. This also atomically commits + * the timestamp computed above. + */ + smp_mb__before_atomic_inc(); + atomic_inc(&dev->_vblank_count[crtc]); + smp_mb__after_atomic_inc(); + } else { + DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n", + crtc, (int) diff_ns); + } + + DRM_WAKEUP(&dev->vbl_queue[crtc]); + drm_handle_vblank_events(dev, crtc); + + spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags); + return true; +} +EXPORT_SYMBOL(drm_handle_vblank); |