Attachment 142574 Details for Bug 106175 – 0001-drm-amd-display-Add-fast-path-for-legacy-cursor-plan.patch

[patch] 0001-drm-amd-display-Add-fast-path-for-legacy-cursor-plan.patch

0001-drm-amd-display-Add-fast-path-for-legacy-cursor-plan.patch (text/plain), 4.65 KB, created by Nicholas Kazlauskas on 2018-11-22 19:30:10 UTC

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Creator: Nicholas Kazlauskas

Created: 2018-11-22 19:30:10 UTC

Size: 4.65 KB

patch

obsolete

>From 8cd15af6653a5f7e2dae850a0beff15025d8f375 Mon Sep 17 00:00:00 2001
>From: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
>Date: Thu, 22 Nov 2018 14:01:41 -0500
>Subject: [PATCH] drm/amd/display: Add fast path for legacy cursor plane
> updates
>
>[Why]
>Legacy cursor plane updates from drm helpers go through the full
>atomic codepath. A high volume of cursor updates through this slow
>code path can subsequent page-flips to skip a vblank interval for
>some clients that try to update on every interval.
>
>This is particularly noticeable for the compton compositor.
>
>[How]
>There's support for this usecase as part of DRM with asynchronous
>plane updates but it doesn't do the required locking needed for
>our usecase.
>
>The fast path introduced for cursor updates in this patch is inspired
>by a similar problem/solution that i915 has previously had.
>
>It updates the cursor plane directly.
>
>Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
>---
> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 102 +++++++++++++++++-
> 1 file changed, 101 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>index fe21bb86b66a..337d5c5b5f26 100644
>--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>@@ -55,6 +55,7 @@
> #include <drm/drmP.h>
> #include <drm/drm_atomic.h>
> #include <drm/drm_atomic_helper.h>
>+#include <drm/drm_atomic_uapi.h>
> #include <drm/drm_dp_mst_helper.h>
> #include <drm/drm_fb_helper.h>
> #include <drm/drm_edid.h>
>@@ -3472,8 +3473,107 @@ void dm_drm_plane_destroy_state(struct drm_plane *plane,
> 	drm_atomic_helper_plane_destroy_state(plane, state);
> }
> 
>+static void handle_cursor_update(struct drm_plane *plane,
>+				 struct drm_plane_state *old_plane_state);
>+
>+static int dm_plane_atomic_check(struct drm_plane *plane,
>+				 struct drm_plane_state *state);
>+
>+static int dm_plane_helper_prepare_fb(struct drm_plane *plane,
>+				      struct drm_plane_state *new_state);
>+
>+static int
>+dm_drm_plane_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_modeset_acquire_ctx *ctx)
>+{
>+	struct drm_crtc_state *crtc_state = crtc->state;
>+	struct drm_plane_state *old_plane_state, *new_plane_state;
>+	int ret;
>+
>+	/* Only support fast updates on cursor planes. */
>+	if (plane->type != DRM_PLANE_TYPE_CURSOR)
>+		goto slow;
>+
>+	/*
>+	 * If the CRTC isn't active or the configuration has changed
>+	 * then we can't do a fast update.
>+	 */
>+	if (!crtc_state->active ||
>+	    drm_atomic_crtc_needs_modeset(crtc_state))
>+		goto slow;
>+
>+	/*
>+	 * Wait for any commits trying to modify the plane to complete
>+	 * before performing the plane update.
>+	 */
>+	old_plane_state = plane->state;
>+
>+	if (old_plane_state->commit &&
>+	    !try_wait_for_completion(&old_plane_state->commit->hw_done))
>+		goto slow;
>+
>+	/*
>+	 * If the basic plane configuration has changed then a fast update
>+	 * can't be performed.
>+	 */
>+	if (old_plane_state->crtc != crtc ||
>+	    old_plane_state->src_w != src_w ||
>+	    old_plane_state->src_h != src_h ||
>+	    old_plane_state->crtc_w != crtc_w ||
>+	    old_plane_state->crtc_h != crtc_h ||
>+	    !old_plane_state->fb != !fb)
>+		goto slow;
>+
>+	new_plane_state = dm_drm_plane_duplicate_state(plane);
>+	if (!new_plane_state)
>+		return -ENOMEM;
>+
>+	drm_atomic_set_fb_for_plane(new_plane_state, fb);
>+
>+	new_plane_state->src_x = src_x;
>+	new_plane_state->src_y = src_y;
>+	new_plane_state->src_w = src_w;
>+	new_plane_state->src_h = src_h;
>+	new_plane_state->crtc_x = crtc_x;
>+	new_plane_state->crtc_y = crtc_y;
>+	new_plane_state->crtc_w = crtc_w;
>+	new_plane_state->crtc_h = crtc_h;
>+
>+	ret = dm_plane_atomic_check(plane, new_plane_state);
>+	if (ret)
>+		goto cleanup;
>+
>+	ret = dm_plane_helper_prepare_fb(plane, new_plane_state);
>+	if (ret)
>+		goto cleanup;
>+
>+	/* Swap state. */
>+	plane->state = new_plane_state;
>+
>+	handle_cursor_update(plane, old_plane_state);
>+
>+cleanup:
>+	if (ret)
>+		dm_drm_plane_destroy_state(plane, new_plane_state);
>+	else
>+		dm_drm_plane_destroy_state(plane, old_plane_state);
>+
>+	return ret;
>+
>+slow:
>+	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, ctx);
>+}
>+
> static const struct drm_plane_funcs dm_plane_funcs = {
>-	.update_plane	= drm_atomic_helper_update_plane,
>+	.update_plane	= dm_drm_plane_update_plane,
> 	.disable_plane	= drm_atomic_helper_disable_plane,
> 	.destroy	= drm_primary_helper_destroy,
> 	.reset = dm_drm_plane_reset,
>-- 
>2.19.1
>

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