[v3,14/16] drm/i915: Tweak BIOS fb reuse check

Commit Message

Ville Syrjälä Jan. 16, 2024, 7:56 a.m. UTC

From: Ville Syrjälä <[e-mail]>

Currently we assume that we bind the BIOS fb exactly into the same
ggtt address where the BIOS left it. That is about to change, and
in order to keep intel_reuse_initial_plane_obj() working as intended
we need to compare the original ggtt offset (called 'base' here)
as opposed to the actual vma ggtt offset we selected. Otherwise
the first plane could change the ggtt offset, and then subsequent
planes would no longer notice that they are in fact using the same
ggtt offset that the first plane was already using. Thus the reuse
check will fail and we proceed to turn off these subsequent planes.

TODO: would probably make more sense to do the pure readout first
for all the planes, then check for fb reuse, and only then proceed
to pin the object into the final location in the ggtt...

Cc: Paz Zcharya <[e-mail]>
Reviewed-by: Andrzej Hajda <[e-mail]>
Signed-off-by: Ville Syrjälä <[e-mail]>
---
 .../drm/i915/display/intel_plane_initial.c    | 34 +++++++++++--------
 1 file changed, 19 insertions(+), 15 deletions(-)

Comments

Paz Zcharya Jan. 30, 2024, 11:26 p.m. UTC | #1

On Tue, Jan 16, 2024 at 09:56:34AM +0200, Ville Syrjala wrote:
> From: Ville Syrjälä <[e-mail]>
> 
> Currently we assume that we bind the BIOS fb exactly into the same
> ggtt address where the BIOS left it. That is about to change, and
> in order to keep intel_reuse_initial_plane_obj() working as intended
> we need to compare the original ggtt offset (called 'base' here)
> as opposed to the actual vma ggtt offset we selected. Otherwise
> the first plane could change the ggtt offset, and then subsequent
> planes would no longer notice that they are in fact using the same
> ggtt offset that the first plane was already using. Thus the reuse
> check will fail and we proceed to turn off these subsequent planes.
> 
> TODO: would probably make more sense to do the pure readout first
> for all the planes, then check for fb reuse, and only then proceed
> to pin the object into the final location in the ggtt...
> 
> Cc: Paz Zcharya <[e-mail]>
> Reviewed-by: Andrzej Hajda <[e-mail]>
> Signed-off-by: Ville Syrjälä <[e-mail]>
Hi Ville,

Thank you so much for this incredible series.
It solves the issue regarding MTL initial plane readout
that Andrzej Hajda and I worked on in
https://patchwork.freedesktop.org/patch/570811/?series=127130&rev=2
In addition, it solved the issue with the new GOP.

I tested it on two different devices with Meteor Lake and it worked perfectly:
no i915 errors, no flickers or observable issues.

Tested-by: Paz Zcharya <[e-mail]>

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_plane_initial.c b/drivers/gpu/drm/i915/display/intel_plane_initial.c
index b7e12b60d68b..82ab98985a09 100644
--- a/drivers/gpu/drm/i915/display/intel_plane_initial.c
+++ b/drivers/gpu/drm/i915/display/intel_plane_initial.c
@@ -13,20 +13,21 @@ 
 #include "intel_plane_initial.h"
 
 static bool
-intel_reuse_initial_plane_obj(struct drm_i915_private *i915,
-			      const struct intel_initial_plane_config *plane_config,
+intel_reuse_initial_plane_obj(struct intel_crtc *this,
+			      const struct intel_initial_plane_config plane_configs[],
 			      struct drm_framebuffer **fb,
 			      struct i915_vma **vma)
 {
+	struct drm_i915_private *i915 = to_i915(this->base.dev);
 	struct intel_crtc *crtc;
 
 	for_each_intel_crtc(&i915->drm, crtc) {
-		struct intel_crtc_state *crtc_state =
-			to_intel_crtc_state(crtc->base.state);
-		struct intel_plane *plane =
+		const struct intel_plane *plane =
 			to_intel_plane(crtc->base.primary);
-		struct intel_plane_state *plane_state =
+		const struct intel_plane_state *plane_state =
 			to_intel_plane_state(plane->base.state);
+		const struct intel_crtc_state *crtc_state =
+			to_intel_crtc_state(crtc->base.state);
 
 		if (!crtc_state->uapi.active)
 			continue;
@@ -34,7 +35,7 @@  intel_reuse_initial_plane_obj(struct drm_i915_private *i915,
 		if (!plane_state->ggtt_vma)
 			continue;
 
-		if (intel_plane_ggtt_offset(plane_state) == plane_config->base) {
+		if (plane_configs[this->pipe].base == plane_configs[crtc->pipe].base) {
 			*fb = plane_state->hw.fb;
 			*vma = plane_state->ggtt_vma;
 			return true;
@@ -265,10 +266,11 @@  intel_alloc_initial_plane_obj(struct intel_crtc *crtc,
 
 static void
 intel_find_initial_plane_obj(struct intel_crtc *crtc,
-			     struct intel_initial_plane_config *plane_config)
+			     struct intel_initial_plane_config plane_configs[])
 {
-	struct drm_device *dev = crtc->base.dev;
-	struct drm_i915_private *dev_priv = to_i915(dev);
+	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+	struct intel_initial_plane_config *plane_config =
+		&plane_configs[crtc->pipe];
 	struct intel_plane *plane =
 		to_intel_plane(crtc->base.primary);
 	struct intel_plane_state *plane_state =
@@ -294,7 +296,7 @@  intel_find_initial_plane_obj(struct intel_crtc *crtc,
 	 * Failed to alloc the obj, check to see if we should share
 	 * an fb with another CRTC instead
 	 */
-	if (intel_reuse_initial_plane_obj(dev_priv, plane_config, &fb, &vma))
+	if (intel_reuse_initial_plane_obj(crtc, plane_configs, &fb, &vma))
 		goto valid_fb;
 
 	/*
@@ -359,10 +361,12 @@  static void plane_config_fini(struct intel_initial_plane_config *plane_config)
 
 void intel_initial_plane_config(struct drm_i915_private *i915)
 {
+	struct intel_initial_plane_config plane_configs[I915_MAX_PIPES] = {};
 	struct intel_crtc *crtc;
 
 	for_each_intel_crtc(&i915->drm, crtc) {
-		struct intel_initial_plane_config plane_config = {};
+		struct intel_initial_plane_config *plane_config =
+			&plane_configs[crtc->pipe];
 
 		if (!to_intel_crtc_state(crtc->base.state)->uapi.active)
 			continue;
@@ -374,14 +378,14 @@  void intel_initial_plane_config(struct drm_i915_private *i915)
 		 * can even allow for smooth boot transitions if the BIOS
 		 * fb is large enough for the active pipe configuration.
 		 */
-		i915->display.funcs.display->get_initial_plane_config(crtc, &plane_config);
+		i915->display.funcs.display->get_initial_plane_config(crtc, plane_config);
 
 		/*
 		 * If the fb is shared between multiple heads, we'll
 		 * just get the first one.
 		 */
-		intel_find_initial_plane_obj(crtc, &plane_config);
+		intel_find_initial_plane_obj(crtc, plane_configs);
 
-		plane_config_fini(&plane_config);
+		plane_config_fini(plane_config);
 	}
 }