[Freedreno] [PATCH] drm/msm/dpu: limit writeback modes according to max_linewidth

[Jessica Zhang]

On 5/13/2022 3:59 PM, Abhinav Kumar wrote:
> Writeback modes were being added according to mode_config.max_width
> but this is assigned to double of max_mixer_width.
> 
> For compositors/clients using a single SSPP, this will fail
> the dpu_plane's atomic check as it checks for max_linewidth.
> 
> Limit writeback modes according to max_linewidth to allow
> even compositors/clients which use only a single SSPP to
> use writeback.
> 
> Fixes: 77b001acdcfeb ("drm/msm/dpu: add the writeback connector layer")
> Reported-by: Jessica Zhang <quic_jesszhan at quicinc.com>

Tested-by: Jessica Zhang <quic_jesszhan at quicinc.com> # Trogdor (SC8170)

> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
> index 7620ffe55779..399115e4e217 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
> @@ -8,8 +8,10 @@
>   static int dpu_wb_conn_get_modes(struct drm_connector *connector)
>   {
>   	struct drm_device *dev = connector->dev;
> +	struct msm_drm_private *priv = dev->dev_private;
> +	struct dpu_kms *dpu_kms = to_dpu_kms(priv->kms);
>   
> -	return drm_add_modes_noedid(connector, dev->mode_config.max_width,
> +	return drm_add_modes_noedid(connector, dpu_kms->catalog->caps->max_linewidth,
>   			dev->mode_config.max_height);
>   }
>   
> -- 
> 2.35.1
>