Re: [PATCH 4/5] drm/msm/dp: report IRQ_HPD as an IRQ-only notification

[Yongxing Mou <yongxing.mou@oss.qualcomm.com>]

On 7/12/2026 6:55 PM, Dmitry Baryshkov wrote:
> On Mon, Jun 29, 2026 at 10:48:06PM +0800, Yongxing Mou wrote:
>> MST reuses the SST connector bridge to propagate HPD IRQ events through
>> the bridge chain.
>>
>> For IRQ_HPD notifications there is no connector state transition to
>> report. Use connector_status_unknown together with
>> DRM_CONNECTOR_DP_IRQ_HPD so that the bridge connector framework treats
>> them as IRQ-only notifications and forwards them without modifying
>> connector state.
>>
>> The DP driver handles IRQ_HPD events based on
>> DRM_CONNECTOR_DP_IRQ_HPD rather than connector status transitions.
>>
>> Signed-off-by: Yongxing Mou <yongxing.mou@oss.qualcomm.com>
>> ---
>>   drivers/gpu/drm/msm/dp/dp_display.c   | 22 +++++++++-------------
>>   drivers/soc/qcom/pmic_glink_altmode.c | 14 +++++++++-----
> 
> And which tree (and why) would be able to merge this patch?
> 
Emm , I will split the patch and reorganize it.
>>   2 files changed, 18 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
>> index bc93b566fbca..4ee391cc7165 100644
>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
>> @@ -1119,14 +1119,10 @@ static irqreturn_t msm_dp_display_irq_thread(int irq, void *dev_id)
>>   		drm_bridge_hpd_notify(dp->msm_dp_display.bridge,
>>   				      connector_status_connected);
>>   
>> -	/* Send HPD as connected and distinguish it in the notifier */
>> -	if (hpd_isr_status & DP_DP_IRQ_HPD_INT_MASK) {
>> -		if (dp->msm_dp_display.mst_active)
>> -			msm_dp_irq_hpd_handle(dp);
>> -		else
>> -			drm_bridge_hpd_notify(dp->msm_dp_display.bridge,
>> -					      connector_status_connected);
>> -	}
>> +	if (hpd_isr_status & DP_DP_IRQ_HPD_INT_MASK)
>> +		drm_bridge_hpd_notify_extra(dp->msm_dp_display.bridge,
>> +					    connector_status_unknown,
> 
> It's _not_ unknown.
> 
Same as my reply to 2/5 -- the status is indeed not unknown here, and
using connector_status_unknown as a sentinel in v1 is not appropriate.
I will fix this in v2 along the direction discussed on 2/5.
>> +					    DRM_CONNECTOR_DP_IRQ_HPD);
> 
> This should be fixed in the MST patchset. You should not be doing any
> actual handling in the ISR routing.
> 
>>   
>>   	ret = IRQ_HANDLED;
>>   
>> @@ -1781,11 +1777,11 @@ void msm_dp_bridge_hpd_notify(struct drm_bridge *bridge,
>>   	drm_dbg_dp(dp->drm_dev, "type=%d link hpd_link_status=0x%x, status=%d\n",
>>   		   msm_dp_display->connector_type, hpd_link_status, status);
>>   
>> -	if (status == connector_status_connected) {
>> -		if (hpd_link_status == ISR_IRQ_HPD_PULSE_COUNT ||
>> -		    extra_status == DRM_CONNECTOR_DP_IRQ_HPD) {
>> -			msm_dp_irq_hpd_handle(dp);
>> -		} else if (hpd_link_status == ISR_HPD_REPLUG_COUNT) {
>> +	if (extra_status == DRM_CONNECTOR_DP_IRQ_HPD ||
>> +	    hpd_link_status == ISR_IRQ_HPD_PULSE_COUNT) {
>> +		msm_dp_irq_hpd_handle(dp);
> 
> ANd here you missed the case when IRQ_HPD is being reported together
> with the first HPD event.
> 
Yes, will fix it next patchset.
>> +	} else if (status == connector_status_connected) {
>> +		if (hpd_link_status == ISR_HPD_REPLUG_COUNT) {
>>   			msm_dp_hpd_unplug_handle(dp);
>>   			msm_dp_hpd_plug_handle(dp);
>>   		} else {
>> diff --git a/drivers/soc/qcom/pmic_glink_altmode.c b/drivers/soc/qcom/pmic_glink_altmode.c
>> index 946eb20b8f83..28ab8cbb5ef9 100644
>> --- a/drivers/soc/qcom/pmic_glink_altmode.c
>> +++ b/drivers/soc/qcom/pmic_glink_altmode.c
>> @@ -373,11 +373,15 @@ static void pmic_glink_altmode_worker(struct work_struct *work)
>>   		else
>>   			conn_status = connector_status_disconnected;
>>   
>> -		drm_aux_hpd_bridge_notify_extra(&alt_port->bridge->dev,
>> -						conn_status,
>> -						alt_port->hpd_irq ?
>> -						DRM_CONNECTOR_DP_IRQ_HPD :
>> -						DRM_CONNECTOR_NO_EXTRA_STATUS);
>> +		if (alt_port->hpd_irq) {
>> +			drm_aux_hpd_bridge_notify_extra(&alt_port->bridge->dev,
>> +							connector_status_unknown,
> 
> And this is completely wrong. The AltMode driver (btw, you also missed
> the normal altmode driver for DP) doesn't know if it should handle the
> events in some way. It should report the HPD and IRQ_HPD as is.
> 
Will fix it next patchset .
>> +							DRM_CONNECTOR_DP_IRQ_HPD);
>> +		} else {
>> +			drm_aux_hpd_bridge_notify_extra(&alt_port->bridge->dev,
>> +							conn_status,
>> +							DRM_CONNECTOR_NO_EXTRA_STATUS);
>> +		}
>>   	} else if (alt_port->mux_ctrl == MUX_CTRL_STATE_TUNNELING) {
>>   		if (alt_port->svid == USB_TYPEC_TBT_SID)
>>   			pmic_glink_altmode_enable_tbt(altmode, alt_port);
>>
>> -- 
>> 2.43.0
>>
>