diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0281-drm-vc4-Add-a-proper-short-circut-path-for-legacy-cu.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.4/0281-drm-vc4-Add-a-proper-short-circut-path-for-legacy-cu.patch | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0281-drm-vc4-Add-a-proper-short-circut-path-for-legacy-cu.patch b/target/linux/brcm2708/patches-4.4/0281-drm-vc4-Add-a-proper-short-circut-path-for-legacy-cu.patch new file mode 100644 index 0000000000..46b0c64d28 --- /dev/null +++ b/target/linux/brcm2708/patches-4.4/0281-drm-vc4-Add-a-proper-short-circut-path-for-legacy-cu.patch @@ -0,0 +1,192 @@ +From a53e75a061bbfb0bb24128a2a9c9961ec20e22ec Mon Sep 17 00:00:00 2001 +From: Eric Anholt <eric@anholt.net> +Date: Wed, 30 Dec 2015 11:50:22 -0800 +Subject: [PATCH 281/304] drm/vc4: Add a proper short-circut path for legacy + cursor updates. + +Previously, on every modeset we would allocate new display list +memory, recompute changed planes, write all of them to the new memory, +and pointed scanout at the new list (which will latch approximately at +the next line of scanout). We let +drm_atomic_helper_wait_for_vblanks() decide whether we needed to wait +for a vblank after a modeset before cleaning up the old state and +letting the next modeset proceed, and on legacy cursor updates we +wouldn't wait. If you moved the cursor fast enough, we could +potentially wrap around the display list memory area and overwrite the +existing display list while it was still being scanned out, resulting +in the HVS scanning out garbage or just halting. + +Instead of making cursor updates wait for scanout to move to the new +display list area (which introduces significant cursor lag in X), we +just rewrite our current display list. + +Signed-off-by: Eric Anholt <eric@anholt.net> +(cherry picked from commit 6674a904d68041d982ffb284d2827410765a097a) +--- + drivers/gpu/drm/vc4/vc4_kms.c | 9 ++++ + drivers/gpu/drm/vc4/vc4_plane.c | 94 ++++++++++++++++++++++++++++++++++++++--- + 2 files changed, 96 insertions(+), 7 deletions(-) + +--- a/drivers/gpu/drm/vc4/vc4_kms.c ++++ b/drivers/gpu/drm/vc4/vc4_kms.c +@@ -49,6 +49,15 @@ vc4_atomic_complete_commit(struct vc4_co + + drm_atomic_helper_commit_modeset_enables(dev, state); + ++ /* Make sure that drm_atomic_helper_wait_for_vblanks() ++ * actually waits for vblank. If we're doing a full atomic ++ * modeset (as opposed to a vc4_update_plane() short circuit), ++ * then we need to wait for scanout to be done with our ++ * display lists before we free it and potentially reallocate ++ * and overwrite the dlist memory with a new modeset. ++ */ ++ state->legacy_cursor_update = false; ++ + drm_atomic_helper_wait_for_vblanks(dev, state); + + drm_atomic_helper_cleanup_planes(dev, state); +--- a/drivers/gpu/drm/vc4/vc4_plane.c ++++ b/drivers/gpu/drm/vc4/vc4_plane.c +@@ -33,8 +33,12 @@ struct vc4_plane_state { + u32 dlist_size; /* Number of dwords allocated for the display list */ + u32 dlist_count; /* Number of used dwords in the display list. */ + +- /* Offset in the dlist to pointer word 0. */ +- u32 pw0_offset; ++ /* Offset in the dlist to various words, for pageflip or ++ * cursor updates. ++ */ ++ u32 pos0_offset; ++ u32 pos2_offset; ++ u32 ptr0_offset; + + /* Offset where the plane's dlist was last stored in the + * hardware at vc4_crtc_atomic_flush() time. +@@ -239,6 +243,7 @@ static int vc4_plane_mode_set(struct drm + SCALER_CTL0_UNITY); + + /* Position Word 0: Image Positions and Alpha Value */ ++ vc4_state->pos0_offset = vc4_state->dlist_count; + vc4_dlist_write(vc4_state, + VC4_SET_FIELD(0xff, SCALER_POS0_FIXED_ALPHA) | + VC4_SET_FIELD(vc4_state->crtc_x, SCALER_POS0_START_X) | +@@ -249,6 +254,7 @@ static int vc4_plane_mode_set(struct drm + */ + + /* Position Word 2: Source Image Size, Alpha Mode */ ++ vc4_state->pos2_offset = vc4_state->dlist_count; + vc4_dlist_write(vc4_state, + VC4_SET_FIELD(format->has_alpha ? + SCALER_POS2_ALPHA_MODE_PIPELINE : +@@ -260,9 +266,8 @@ static int vc4_plane_mode_set(struct drm + /* Position Word 3: Context. Written by the HVS. */ + vc4_dlist_write(vc4_state, 0xc0c0c0c0); + +- vc4_state->pw0_offset = vc4_state->dlist_count; +- + /* Pointer Word 0: RGB / Y Pointer */ ++ vc4_state->ptr0_offset = vc4_state->dlist_count; + vc4_dlist_write(vc4_state, bo->paddr + vc4_state->offset); + + /* Pointer Context Word 0: Written by the HVS */ +@@ -348,13 +353,13 @@ void vc4_plane_async_set_fb(struct drm_p + * scanout will start from this address as soon as the FIFO + * needs to refill with pixels. + */ +- writel(addr, &vc4_state->hw_dlist[vc4_state->pw0_offset]); ++ writel(addr, &vc4_state->hw_dlist[vc4_state->ptr0_offset]); + + /* Also update the CPU-side dlist copy, so that any later + * atomic updates that don't do a new modeset on our plane + * also use our updated address. + */ +- vc4_state->dlist[vc4_state->pw0_offset] = addr; ++ vc4_state->dlist[vc4_state->ptr0_offset] = addr; + } + + static const struct drm_plane_helper_funcs vc4_plane_helper_funcs = { +@@ -370,8 +375,83 @@ static void vc4_plane_destroy(struct drm + drm_plane_cleanup(plane); + } + ++/* Implements immediate (non-vblank-synced) updates of the cursor ++ * position, or falls back to the atomic helper otherwise. ++ */ ++static int ++vc4_update_plane(struct drm_plane *plane, ++ struct drm_crtc *crtc, ++ struct drm_framebuffer *fb, ++ int crtc_x, int crtc_y, ++ unsigned int crtc_w, unsigned int crtc_h, ++ uint32_t src_x, uint32_t src_y, ++ uint32_t src_w, uint32_t src_h) ++{ ++ struct drm_plane_state *plane_state; ++ struct vc4_plane_state *vc4_state; ++ ++ if (plane != crtc->cursor) ++ goto out; ++ ++ plane_state = plane->state; ++ vc4_state = to_vc4_plane_state(plane_state); ++ ++ if (!plane_state) ++ goto out; ++ ++ /* If we're changing the cursor contents, do that in the ++ * normal vblank-synced atomic path. ++ */ ++ if (fb != plane_state->fb) ++ goto out; ++ ++ /* No configuring new scaling in the fast path. */ ++ if (crtc_w != plane_state->crtc_w || ++ crtc_h != plane_state->crtc_h || ++ src_w != plane_state->src_w || ++ src_h != plane_state->src_h) { ++ goto out; ++ } ++ ++ /* Set the cursor's position on the screen. This is the ++ * expected change from the drm_mode_cursor_universal() ++ * helper. ++ */ ++ plane_state->crtc_x = crtc_x; ++ plane_state->crtc_y = crtc_y; ++ ++ /* Allow changing the start position within the cursor BO, if ++ * that matters. ++ */ ++ plane_state->src_x = src_x; ++ plane_state->src_y = src_y; ++ ++ /* Update the display list based on the new crtc_x/y. */ ++ vc4_plane_atomic_check(plane, plane_state); ++ ++ /* Note that we can't just call vc4_plane_write_dlist() ++ * because that would smash the context data that the HVS is ++ * currently using. ++ */ ++ writel(vc4_state->dlist[vc4_state->pos0_offset], ++ &vc4_state->hw_dlist[vc4_state->pos0_offset]); ++ writel(vc4_state->dlist[vc4_state->pos2_offset], ++ &vc4_state->hw_dlist[vc4_state->pos2_offset]); ++ writel(vc4_state->dlist[vc4_state->ptr0_offset], ++ &vc4_state->hw_dlist[vc4_state->ptr0_offset]); ++ ++ return 0; ++ ++out: ++ return drm_atomic_helper_update_plane(plane, crtc, fb, ++ crtc_x, crtc_y, ++ crtc_w, crtc_h, ++ src_x, src_y, ++ src_w, src_h); ++} ++ + static const struct drm_plane_funcs vc4_plane_funcs = { +- .update_plane = drm_atomic_helper_update_plane, ++ .update_plane = vc4_update_plane, + .disable_plane = drm_atomic_helper_disable_plane, + .destroy = vc4_plane_destroy, + .set_property = NULL, |