[PATCH 05/20] drm/i915/dp: Handle the RX_CAP_CHANGED HPD IRQ

[Luca Coelho]

On Thu, 2025-06-26 at 11:20 +0300, Imre Deak wrote:
> From: Imre Deak <imre.deak at gmail.com>
> 
> Handle the RX_CAP_CHANGED IRQ, which a sink can use to indicate a DPRX
> capability change without disconnecting and reconnecting itself (i.e.
> through a short vs. long HPD pulse). Handle the IRQ by doing a full
> connector detection.
> 
> Signed-off-by: Imre Deak <imre.deak at gmail.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 453416b9e9bec..c2eadfa060c2d 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -5099,7 +5099,7 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
>  
>  		drm_dbg_kms(display->drm, "DPRX ESI: %4ph\n", esi);
>  
> -		ack[3] |= esi[3] & (LINK_STATUS_CHANGED | DP_TUNNELING_IRQ);
> +		ack[3] |= esi[3] & (RX_CAP_CHANGED | LINK_STATUS_CHANGED | DP_TUNNELING_IRQ);
>  
>  		intel_dp_mst_hpd_irq(intel_dp, esi, ack);
>  
> @@ -5112,6 +5112,9 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp)
>  		if (ack[1] & (DP_DOWN_REP_MSG_RDY | DP_UP_REQ_MSG_RDY))
>  			drm_dp_mst_hpd_irq_send_new_request(&intel_dp->mst.mgr);
>  
> +		if (ack[3] & RX_CAP_CHANGED)
> +			reprobe_needed = true;
> +
>  		if ((ack[3] & LINK_STATUS_CHANGED) || intel_dp->link.force_retrain)
>  			intel_dp_check_link_state(intel_dp);
>  
> @@ -5424,6 +5427,9 @@ static bool intel_dp_check_link_service_irq(struct intel_dp *intel_dp)
>  			       DP_LINK_SERVICE_IRQ_VECTOR_ESI0, val) != 1)
>  		return false;
>  
> +	if (val & RX_CAP_CHANGED)
> +		reprobe_needed = true;
> +
>  	if (val & HDMI_LINK_STATUS_CHANGED)
>  		intel_dp_handle_hdmi_link_status_change(intel_dp);
>  

Same question as to the previous patch.  What happens if the interrupt
is not actually handled?

--
Cheers,
Luca.