Re: [PATCH 11/20] drm/i915/dp: Reprobe connector if getting/acking device IRQs fails

[Jani Nikula <jani.nikula@linux.intel.com>]

On Thu, 26 Jun 2025, Imre Deak <imre.deak@intel.com> wrote:
> From: Imre Deak <imre.deak@gmail.com>
>
> An AUX access failure during HPD IRQ handling should be handled by
> falling back to a full connector detection, ensure that if the failure
> happens while reading/acking a device service IRQ.
>
> Signed-off-by: Imre Deak <imre.deak@gmail.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 7793a72983abd..7eb208d2c321b 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -5393,16 +5393,20 @@ void intel_dp_check_link_state(struct intel_dp *intel_dp)
>  	intel_encoder_link_check_queue_work(encoder, 0);
>  }
>  
> -static void intel_dp_check_device_service_irq(struct intel_dp *intel_dp)
> +static bool intel_dp_check_device_service_irq(struct intel_dp *intel_dp)

I don't think "check" is very intuitive in function names. Check
something, but then what? Is it like an assert or does it do something
active or what?

What does a boolean return from a check function mean?

It's not obvious to the reader at all.

>  {
>  	struct intel_display *display = to_intel_display(intel_dp);
>  	u8 val;
>  
>  	if (drm_dp_dpcd_readb(&intel_dp->aux,
> -			      DP_DEVICE_SERVICE_IRQ_VECTOR, &val) != 1 || !val)
> -		return;
> +			      DP_DEVICE_SERVICE_IRQ_VECTOR, &val) != 1)
> +		return true;

Looks like true means the check failed... while usually true for boolean
functions means success.

>  
> -	drm_dp_dpcd_writeb(&intel_dp->aux, DP_DEVICE_SERVICE_IRQ_VECTOR, val);
> +	if (!val)
> +		return false;
> +
> +	if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_DEVICE_SERVICE_IRQ_VECTOR, val) != 1)
> +		return true;
>  
>  	if (val & DP_AUTOMATED_TEST_REQUEST)
>  		intel_dp_test_request(intel_dp);

Whoa, it's not a *check* function at all?! It actually *handles* the
service irqs.

Can we rephrase the function name?

int intel_dp_handle_device_service_irq() and int returns maybe?


BR,
Jani.

> @@ -5412,6 +5416,8 @@ static void intel_dp_check_device_service_irq(struct intel_dp *intel_dp)
>  
>  	if (val & DP_SINK_SPECIFIC_IRQ)
>  		drm_dbg_kms(display->drm, "Sink specific irq unhandled\n");
> +
> +	return false;
>  }
>  
>  static bool intel_dp_check_link_service_irq(struct intel_dp *intel_dp)
> @@ -5476,8 +5482,11 @@ intel_dp_short_pulse(struct intel_dp *intel_dp)
>  		/* No need to proceed if we are going to do full detect */
>  		return false;
>  
> -	intel_dp_check_device_service_irq(intel_dp);
> -	reprobe_needed = intel_dp_check_link_service_irq(intel_dp);
> +	if (intel_dp_check_device_service_irq(intel_dp))
> +		reprobe_needed = true;
> +
> +	if (intel_dp_check_link_service_irq(intel_dp))
> +		reprobe_needed = true;
>  
>  	/* Handle CEC interrupts, if any */
>  	drm_dp_cec_irq(&intel_dp->aux);

-- 
Jani Nikula, Intel