Re: [PATCH RESEND v5 11/25] drm/msm/dp: move link-level teardown from display_disable to display_unprepare

[Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>]

On Mon, Jun 29, 2026 at 10:14:32PM +0800, Yongxing Mou wrote:
> From: Abhinav Kumar <quic_abhinavk@quicinc.com>
> 
> msm_dp_display_disable() currently mixes stream-level shutdown
> (disable VSC SDP, off pixel clk, clear power_on) with link-level
> teardown (PSM config when sink_count==0, off_link, PHY re-init or
> host PHY exit).
> 
> For DP MST the same link is shared across multiple streams, so
> disabling one stream must not tear down the link. Move the
> link-level steps into msm_dp_display_unprepare() so that
> display_disable() handles only the per-stream sequence, mirroring
> the split already present on the prepare path
> (display_prepare_link vs display_set_mode / display_enable).
> 
> SST behaviour is unchanged: atomic_post_disable() still calls
> display_disable() followed by display_unprepare() in the same
> order, and the cached dp->panel used inside unprepare is the same
> panel that was previously passed in.
> 
> Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
> Signed-off-by: Yongxing Mou <yongxing.mou@oss.qualcomm.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_display.c | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index 1af56c84b82e..1680a67284a7 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -731,18 +731,6 @@ static int msm_dp_display_disable(struct msm_dp_display_private *dp,
>  
>  	msm_dp_ctrl_off_pixel_clk(dp->ctrl, msm_dp_panel->stream_id);
>  
> -	/* dongle is still connected but sinks are disconnected */
> -	if (dp->link->sink_count == 0)
> -		msm_dp_link_psm_config(dp->link, &msm_dp_panel->link_info, true);
> -
> -	msm_dp_ctrl_off_link(dp->ctrl, dp->panel);
> -
> -	if (dp->link->sink_count == 0)
> -		/* re-init the PHY so that we can listen to Dongle disconnect */
> -		msm_dp_ctrl_reinit_phy(dp->ctrl);
> -	else
> -		msm_dp_display_host_phy_exit(dp);
> -
>  	msm_dp_display->power_on = false;

The list is no longer powred on at this point. So, this is wrong.

>  
>  	drm_dbg_dp(dp->drm_dev, "sink count: %d\n", dp->link->sink_count);
> @@ -1533,6 +1521,18 @@ static void msm_dp_display_unprepare(struct msm_dp_display_private *dp)
>  {
>  	struct msm_dp *msm_dp_display = &dp->msm_dp_display;
>  
> +	/* dongle is still connected but sinks are disconnected */
> +	if (dp->link->sink_count == 0)
> +		msm_dp_link_psm_config(dp->link, &dp->panel->link_info, true);
> +
> +	msm_dp_ctrl_off_link(dp->ctrl, dp->panel);
> +
> +	if (dp->link->sink_count == 0)
> +		/* re-init the PHY so that we can listen to Dongle disconnect */
> +		msm_dp_ctrl_reinit_phy(dp->ctrl);
> +	else
> +		msm_dp_display_host_phy_exit(dp);
> +
>  	pm_runtime_put_sync(&msm_dp_display->pdev->dev);
>  
>  	drm_dbg_dp(dp->drm_dev, "type=%d Done\n", msm_dp_display->connector_type);
> 
> -- 
> 2.43.0
> 

-- 
With best wishes
Dmitry