[PATCH 1/4] drm/msm/dp: remove redundant checks related to ST_DISPLAY_OFF in plug/irq_ipd handlers

[Dmitry Baryshkov]

On Mon, Dec 02, 2024 at 04:39:00PM -0800, Abhinav Kumar wrote:
> In commit 8ede2ecc3e5ee ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets"),
> checks were introduced to avoid handling any plug or irq hpd events in
> ST_DISPLAY_OFF state.
> 
> Even if we do get hpd events, after the bridge was disabled,
> it should get handled. Moreover, its unclear under what circumstances
> these events will fire because ST_DISPLAY_OFF means that the link was
> still connected but only the bridge was disabled. If the link was untouched,
> then interrupts shouldn't fire.

What about the link being untouched, but the monitor being toggled
somehow, which might generate HPD / attention events?

> 
> Even in the case of the DP compliance equipment, it should be raising these
> interrupts during the start of the test which is usually accompanied with either
> a HPD pulse or a IRQ HPD but after the bridge is disabled it should be fine
> to handle these anyway. In the absence of a better reason to keep these checks,
> drop these and if any other issues do arise, it should be handled in a different
> way.
> 
> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
> ---
>  drivers/gpu/drm/msm/dp/dp_display.c | 10 ----------
>  1 file changed, 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
> index aba925aab7ad..992184cc17e4 100644
> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> @@ -562,11 +562,6 @@ static int msm_dp_hpd_plug_handle(struct msm_dp_display_private *dp, u32 data)
>  	drm_dbg_dp(dp->drm_dev, "Before, type=%d hpd_state=%d\n",
>  			dp->msm_dp_display.connector_type, state);
>  
> -	if (state == ST_DISPLAY_OFF) {
> -		mutex_unlock(&dp->event_mutex);
> -		return 0;
> -	}
> -
>  	if (state == ST_MAINLINK_READY || state == ST_CONNECTED) {
>  		mutex_unlock(&dp->event_mutex);
>  		return 0;
> @@ -689,11 +684,6 @@ static int msm_dp_irq_hpd_handle(struct msm_dp_display_private *dp, u32 data)
>  	drm_dbg_dp(dp->drm_dev, "Before, type=%d hpd_state=%d\n",
>  			dp->msm_dp_display.connector_type, state);
>  
> -	if (state == ST_DISPLAY_OFF) {
> -		mutex_unlock(&dp->event_mutex);
> -		return 0;
> -	}
> -
>  	if (state == ST_MAINLINK_READY || state == ST_DISCONNECT_PENDING) {
>  		/* wait until ST_CONNECTED */
>  		msm_dp_add_event(dp, EV_IRQ_HPD_INT, 0, 1); /* delay = 1 */
> 
> -- 
> 2.34.1
> 

-- 
With best wishes
Dmitry