Re: [PATCH] drm/amd/display: do not copy invalid CRTC timing info

[Alex Hung]

Hi Gergo,

Thanks for the patch. I am sending this patch for testing and I will 
update test result next week.


On 4/2/25 11:03, Gergo Koteles wrote:
Since b255ce4388e0, it is possible that the CRTC timing
information for the preferred mode has not yet been
calculated while amdgpu_dm_connector_mode_valid() is running.

In this case use the CRTC timing information of the actual mode.

Fixes: b255ce4388e0 ("drm/amdgpu: don't change mode in 
amdgpu_dm_connector_mode_valid()")
Closes: 
https://lore.kernel.org/all/ed09edb167e74167a694f4854102a3de6d2f1433.ca...@irl.hu/
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4085
Signed-off-by: Gergo Koteles <so...@irl.hu>
---
  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 ++++++------
  1 file changed, 6 insertions(+), 6 deletions(-)

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 bae83a129b5f..0eb25cdcb52f 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -6500,12 +6500,12 @@ decide_crtc_timing_for_drm_display_mode(struct 
drm_display_mode *drm_mode,
                                        const struct drm_display_mode 
*native_mode,
                                        bool scale_enabled)
  {
-       if (scale_enabled) {
-               copy_crtc_timing_for_drm_display_mode(native_mode, drm_mode);
-       } else if (native_mode->clock == drm_mode->clock &&
-                       native_mode->htotal == drm_mode->htotal &&
-                       native_mode->vtotal == drm_mode->vtotal) {
-               copy_crtc_timing_for_drm_display_mode(native_mode, drm_mode);
+       if (scale_enabled || (
+           native_mode->clock == drm_mode->clock &&
+           native_mode->htotal == drm_mode->htotal &&
+           native_mode->vtotal == drm_mode->vtotal)) {
+               if (native_mode->crtc_clock)
+                       copy_crtc_timing_for_drm_display_mode(native_mode, 
drm_mode);
        } else {
                /* no scaling nor amdgpu inserted, no need to patch */
        }