[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.camel@irl.hu/
> Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4085
> Signed-off-by: Gergo Koteles <soyer at 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 */
>   	}