Re: [PATCH v2] drm/msm/dp: always add fail-safe mode into connector mode list

[Kuogee Hsieh <quic_khsieh@quicinc.com>]

Hi Stephen,

Are you have more comments?


On 1/24/2022 3:17 PM, Kuogee Hsieh wrote:
> Some of DP link compliant test expects to return fail-safe mode
> if prefer detailed timing mode can not be supported by mainlink's
> lane and rate after link training. Therefore add fail-safe mode
> into connector mode list as backup mode. This patch fixes test
> case 4.2.2.1.
>
> Changes in v2:
> -- add Fixes text string
>
> Fixes: 4b85d405cfe9 ( "drm/msm/dp: reduce link rate if failed at link training 1")
> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
> ---
>   drivers/gpu/drm/msm/dp/dp_panel.c | 5 +++++
>   1 file changed, 5 insertions(+)
>
> diff --git a/drivers/gpu/drm/msm/dp/dp_panel.c b/drivers/gpu/drm/msm/dp/dp_panel.c
> index 71db10c..f141872 100644
> --- a/drivers/gpu/drm/msm/dp/dp_panel.c
> +++ b/drivers/gpu/drm/msm/dp/dp_panel.c
> @@ -212,6 +212,11 @@ int dp_panel_read_sink_caps(struct dp_panel *dp_panel,
>   		if (drm_add_modes_noedid(connector, 640, 480))
>   			drm_set_preferred_mode(connector, 640, 480);
>   		mutex_unlock(&connector->dev->mode_config.mutex);
> +	} else {
> +		/* always add fail-safe mode as backup mode */
> +		mutex_lock(&connector->dev->mode_config.mutex);
> +		drm_add_modes_noedid(connector, 640, 480);
> +		mutex_unlock(&connector->dev->mode_config.mutex);
>   	}
>   
>   	if (panel->aux_cfg_update_done) {