Re: [PATCH v11 3/5] drm/i915/display: Acomodate format check in intel_plane_can_async_flip()

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Fri, Mar 28, 2025 at 09:26:22PM +0530, Arun R Murthy wrote:
> The function intel_plane_can_async_flip() checks for async supported
> modifier, add format support check also in the same function.
> 
> Note: on ADL the surface base addr is required to be 16k aligned and if
> not might generate DMAR and GGTT faults leading to glitches.

What we want to highlight is that this *changes* the alignment from
16K to 4K for planar formats on ADL.

> 
> v11: Move filtering Indexed 8bit to a separate patch (Ville)
> v12: correct the commit msg and remove unwanted debug print (Ville)
> 
> Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
> ---
>  drivers/gpu/drm/i915/display/i9xx_plane.c          |  4 ++--
>  drivers/gpu/drm/i915/display/intel_atomic_plane.c  |  6 +++++-
>  drivers/gpu/drm/i915/display/intel_atomic_plane.h  |  3 ++-
>  drivers/gpu/drm/i915/display/intel_display.c       | 14 ++++----------
>  drivers/gpu/drm/i915/display/skl_universal_plane.c |  2 +-
>  5 files changed, 14 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/i9xx_plane.c b/drivers/gpu/drm/i915/display/i9xx_plane.c
> index 5e8344fdfc28a311dc0632bb848a0e08f9e6c6d2..20c47de6d8bfd1d8ddafae02ed68370df799e22b 100644
> --- a/drivers/gpu/drm/i915/display/i9xx_plane.c
> +++ b/drivers/gpu/drm/i915/display/i9xx_plane.c
> @@ -828,7 +828,7 @@ unsigned int vlv_plane_min_alignment(struct intel_plane *plane,
>  {
>  	struct intel_display *display = to_intel_display(plane);
>  
> -	if (intel_plane_can_async_flip(plane, fb->modifier))
> +	if (intel_plane_can_async_flip(plane, fb->format->format, fb->modifier))
>  		return 256 * 1024;
>  
>  	/* FIXME undocumented so not sure what's actually needed */
> @@ -852,7 +852,7 @@ static unsigned int g4x_primary_min_alignment(struct intel_plane *plane,
>  {
>  	struct intel_display *display = to_intel_display(plane);
>  
> -	if (intel_plane_can_async_flip(plane, fb->modifier))
> +	if (intel_plane_can_async_flip(plane, fb->format->format, fb->modifier))
>  		return 256 * 1024;
>  
>  	if (intel_scanout_needs_vtd_wa(display))
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> index 7276179df878658b7053fe6d8dc37b69f19625e3..1ec730047759cb22b3e0fabfd2eaddbc1bc865af 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> @@ -174,8 +174,12 @@ bool intel_plane_needs_physical(struct intel_plane *plane)
>  		DISPLAY_INFO(display)->cursor_needs_physical;
>  }
>  
> -bool intel_plane_can_async_flip(struct intel_plane *plane, u64 modifier)
> +bool intel_plane_can_async_flip(struct intel_plane *plane, u32 format,
> +				u64 modifier)
>  {
> +	if (intel_format_info_is_yuv_semiplanar(drm_format_info(format), modifier))
> +		return false;
> +
>  	return plane->can_async_flip && plane->can_async_flip(modifier);
>  }
>  
> diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.h b/drivers/gpu/drm/i915/display/intel_atomic_plane.h
> index 6efac923dcbc757e6f68564cbef2919c920f13cb..772a12aa9c6997d77b9393f964e91f3e8747d149 100644
> --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.h
> +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.h
> @@ -21,7 +21,8 @@ enum plane_id;
>  
>  struct intel_plane *
>  intel_crtc_get_plane(struct intel_crtc *crtc, enum plane_id plane_id);
> -bool intel_plane_can_async_flip(struct intel_plane *plane, u64 modifier);
> +bool intel_plane_can_async_flip(struct intel_plane *plane, u32 format,
> +				u64 modifier);
>  unsigned int intel_adjusted_rate(const struct drm_rect *src,
>  				 const struct drm_rect *dst,
>  				 unsigned int rate);
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 103173836abf9ea3a9094d2726d3dfbc94023ea6..542fe21a1f32588a8f4d9e133475b15c4132c4c9 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -5998,22 +5998,16 @@ static int intel_async_flip_check_hw(struct intel_atomic_state *state, struct in
>  		if (!plane->async_flip)
>  			continue;
>  
> -		if (!intel_plane_can_async_flip(plane, new_plane_state->hw.fb->modifier)) {
> +		if (!intel_plane_can_async_flip(plane, new_plane_state->hw.fb->format->format,
> +						new_plane_state->hw.fb->modifier)) {
>  			drm_dbg_kms(display->drm,
> -				    "[PLANE:%d:%s] Modifier 0x%llx does not support async flip\n",
> +				    "[PLANE:%d:%s] Format %p4cc Modifier 0x%llx does not support async flip\n",

I would make that

"... pixel format %p4cc / modifier 0x%llx ..."

to be consistent with some existing printk in intel_fb.c.

Apart from those lgtm
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>


>  				    plane->base.base.id, plane->base.name,
> +				    &new_plane_state->hw.fb->format->format,
>  				    new_plane_state->hw.fb->modifier);
>  			return -EINVAL;
>  		}
>  
> -		if (intel_format_info_is_yuv_semiplanar(new_plane_state->hw.fb->format,
> -							new_plane_state->hw.fb->modifier)) {
> -			drm_dbg_kms(display->drm,
> -				    "[PLANE:%d:%s] Planar formats do not support async flips\n",
> -				    plane->base.base.id, plane->base.name);
> -			return -EINVAL;
> -		}
> -
>  		/*
>  		 * We turn the first async flip request into a sync flip
>  		 * so that we can reconfigure the plane (eg. change modifier).
> diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane.c b/drivers/gpu/drm/i915/display/skl_universal_plane.c
> index 8739195aba696d13b30e1b978c8b2bb5e188119b..8f6170a5c108a000582f3415f78bad279254d8cf 100644
> --- a/drivers/gpu/drm/i915/display/skl_universal_plane.c
> +++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c
> @@ -601,7 +601,7 @@ static u32 tgl_plane_min_alignment(struct intel_plane *plane,
>  	 * Figure out what's going on here...
>  	 */
>  	if (display->platform.alderlake_p &&
> -	    intel_plane_can_async_flip(plane, fb->modifier))
> +	    intel_plane_can_async_flip(plane, fb->format->format, fb->modifier))
>  		return mult * 16 * 1024;
>  
>  	switch (fb->modifier) {
> 
> -- 
> 2.25.1

-- 
Ville Syrjälä
Intel