diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0451-drm-vc4-Make-pageflip-completion-handling-more-robus.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0451-drm-vc4-Make-pageflip-completion-handling-more-robus.patch | 126 |
1 files changed, 0 insertions, 126 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0451-drm-vc4-Make-pageflip-completion-handling-more-robus.patch b/target/linux/brcm2708/patches-4.4/0451-drm-vc4-Make-pageflip-completion-handling-more-robus.patch deleted file mode 100644 index 88b8c030cd..0000000000 --- a/target/linux/brcm2708/patches-4.4/0451-drm-vc4-Make-pageflip-completion-handling-more-robus.patch +++ /dev/null @@ -1,126 +0,0 @@ -From 8a7bf555e2fa4a6f683a06e3b474cf4751181557 Mon Sep 17 00:00:00 2001 -From: Mario Kleiner <mario.kleiner.de@gmail.com> -Date: Wed, 18 May 2016 14:02:46 +0200 -Subject: [PATCH] drm/vc4: Make pageflip completion handling more robust. - -Protect both the setup of the pageflip event and the -latching of the new requested displaylist head pointer -by the event lock, so we can't get into a situation -where vc4_atomic_flush latches the new display list via -HVS_WRITE, then immediately gets preempted before queueing -the pageflip event, then the page-flip completes in hw and -the vc4_crtc_handle_page_flip() runs and no-ops due to -lack of a pending pageflip event, then vc4_atomic_flush -continues and only then queues the pageflip event - after -the page flip handling already no-oped. This would cause -flip completion handling only at the next vblank - one -frame too late. - -In vc4_crtc_handle_page_flip() check the actual DL head -pointer in SCALER_DISPLACTX against the requested pointer -for page flip to make sure that the flip actually really -completed in the current vblank and doesn't get deferred -to the next one because the DL head pointer was written -a bit too late into SCALER_DISPLISTX, after start of -vblank, and missed the boat. This avoids handling a -pageflip completion too early - one frame too early. - -According to Eric, DL head pointer updates which were -written into the HVS DISPLISTX reg get committed to hardware -at the last pixel of active scanout. Our vblank interrupt -handler, as triggered by PV_INT_VFP_START irq, gets to run -earliest at the first pixel of HBLANK at the end of the -last scanline of active scanout, ie. vblank irq handling -runs at least 1 pixel duration after a potential pageflip -completion happened in hardware. - -This ordering of events in the hardware, together with the -lock protection and SCALER_DISPLACTX sampling of this patch, -guarantees that pageflip completion handling only runs at -exactly the vblank irq of actual pageflip completion in all -cases. - -Background info from Eric about the relative timing of -HVS, PV's and trigger points for interrupts, DL updates: - -https://lists.freedesktop.org/archives/dri-devel/2016-May/107510.html - -Tested on RPi 2B with hardware timing measurement equipment -and shown to no longer complete flips too early or too late. - -Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com> -Reviewed-by: Eric Anholt <eric@anholt.net> -(cherry picked from commit 56d1fe0979dc9b73c1c12ee07722ac380d42a0c4) ---- - drivers/gpu/drm/vc4/vc4_crtc.c | 28 ++++++++++++++++++---------- - drivers/gpu/drm/vc4/vc4_regs.h | 4 ++++ - 2 files changed, 22 insertions(+), 10 deletions(-) - ---- a/drivers/gpu/drm/vc4/vc4_crtc.c -+++ b/drivers/gpu/drm/vc4/vc4_crtc.c -@@ -465,14 +465,6 @@ static void vc4_crtc_atomic_flush(struct - - WARN_ON_ONCE(dlist_next - dlist_start != vc4_state->mm.size); - -- HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel), -- vc4_state->mm.start); -- -- if (debug_dump_regs) { -- DRM_INFO("CRTC %d HVS after:\n", drm_crtc_index(crtc)); -- vc4_hvs_dump_state(dev); -- } -- - if (crtc->state->event) { - unsigned long flags; - -@@ -482,8 +474,20 @@ static void vc4_crtc_atomic_flush(struct - - spin_lock_irqsave(&dev->event_lock, flags); - vc4_crtc->event = crtc->state->event; -- spin_unlock_irqrestore(&dev->event_lock, flags); - crtc->state->event = NULL; -+ -+ HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel), -+ vc4_state->mm.start); -+ -+ spin_unlock_irqrestore(&dev->event_lock, flags); -+ } else { -+ HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel), -+ vc4_state->mm.start); -+ } -+ -+ if (debug_dump_regs) { -+ DRM_INFO("CRTC %d HVS after:\n", drm_crtc_index(crtc)); -+ vc4_hvs_dump_state(dev); - } - } - -@@ -509,10 +513,14 @@ static void vc4_crtc_handle_page_flip(st - { - struct drm_crtc *crtc = &vc4_crtc->base; - struct drm_device *dev = crtc->dev; -+ struct vc4_dev *vc4 = to_vc4_dev(dev); -+ struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(crtc->state); -+ u32 chan = vc4_crtc->channel; - unsigned long flags; - - spin_lock_irqsave(&dev->event_lock, flags); -- if (vc4_crtc->event) { -+ if (vc4_crtc->event && -+ (vc4_state->mm.start == HVS_READ(SCALER_DISPLACTX(chan)))) { - drm_crtc_send_vblank_event(crtc, vc4_crtc->event); - vc4_crtc->event = NULL; - drm_crtc_vblank_put(crtc); ---- a/drivers/gpu/drm/vc4/vc4_regs.h -+++ b/drivers/gpu/drm/vc4/vc4_regs.h -@@ -343,6 +343,10 @@ - #define SCALER_DISPLACT0 0x00000030 - #define SCALER_DISPLACT1 0x00000034 - #define SCALER_DISPLACT2 0x00000038 -+#define SCALER_DISPLACTX(x) (SCALER_DISPLACT0 + \ -+ (x) * (SCALER_DISPLACT1 - \ -+ SCALER_DISPLACT0)) -+ - #define SCALER_DISPCTRL0 0x00000040 - # define SCALER_DISPCTRLX_ENABLE BIT(31) - # define SCALER_DISPCTRLX_RESET BIT(30) |