[PATCH] drm/msm/dpu: limit wb modes based on max_mixer_width

[Dmitry Baryshkov]

On 16/06/2022 22:26, Abhinav Kumar wrote:
> As explained in [1], using max_linewidth to limit the modes
> does not seem to remove 4K modes on chipsets such as
> sm8250 where the max_linewidth actually supports 4k.
> 
> This would have been alright if dual SSPP support was
> present but otherwise fails the per SSPP bandwidth check.
> 
> The ideal way to implement this would be to filter out
> the modes which will exceed the bandwidth check by computing
> it.
> 
> But this would be an exhaustive solution till we have
> dual SSPP support.
> 
> Let's instead use max_mixer_width to limit the modes.
> 
> max_mixer_width still remains 2560 on sm8250 so even if
> the max_linewidth is 4096, the only way 4k modes could have
> been supported is to have source split enabled on the SSPP.
> 
> Since source split support is not enabled yet in DPU driver,
> enforce max_mixer_width as the upper limit on the modes.
> 
> [1] https://patchwork.freedesktop.org/patch/489662/
> 
> Fixes: e67dcecda06f ("drm/msm/dpu: limit writeback modes according to max_linewidth")
> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>


-- 
With best wishes
Dmitry