Re: [PATCH 1/2] drm/i915/display: Add macro for checking 3 DSC engines

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 14 Apr 2025, Ankit Nautiyal <ankit.k.nautiyal@intel.com> wrote:
> 3 DSC engines per pipe is currently supported only for BMG.
> Add a macro to check whether a platform supports 3 DSC engines per pipe.

Nitpick, feels like a macro returning the number of DSC engines per pipe
would be more generic. Like, would you also add HAS_DSC_2ENGINES() and
HAS_DSC_4ENGINES() if you needed to know that? But I guess we can go
with what you have for the immediate fix.

However, adding the tiniest macro and its only user in separate patches,
for something that needs to be backported to stable, seems like erring
on the side of splitting up patches too much.

BR,
Jani.


>
> v2:Fix Typo in macro argument. (Suraj).
> Added fixes tag.
>
> Bspec: 50175
> Fixes: be7f5fcdf4a0 ("drm/i915/dp: Enable 3 DSC engines for 12 slices")
> Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> Cc: Suraj Kandpal <suraj.kandpal@intel.com>
> Cc: <stable@vger.kernel.org> # v6.14+
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display_device.h | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_device.h b/drivers/gpu/drm/i915/display/intel_display_device.h
> index 368b0d3417c2..87c666792c0d 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_device.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_device.h
> @@ -163,6 +163,7 @@ struct intel_display_platforms {
>  #define HAS_DP_MST(__display)		(DISPLAY_INFO(__display)->has_dp_mst)
>  #define HAS_DSB(__display)		(DISPLAY_INFO(__display)->has_dsb)
>  #define HAS_DSC(__display)		(DISPLAY_RUNTIME_INFO(__display)->has_dsc)
> +#define HAS_DSC_3ENGINES(__display)	(DISPLAY_VERx100(__display) == 1401 && HAS_DSC(__display))
>  #define HAS_DSC_MST(__display)		(DISPLAY_VER(__display) >= 12 && HAS_DSC(__display))
>  #define HAS_FBC(__display)		(DISPLAY_RUNTIME_INFO(__display)->fbc_mask != 0)
>  #define HAS_FBC_DIRTY_RECT(__display)	(DISPLAY_VER(__display) >= 30)

-- 
Jani Nikula, Intel