Re: [PATCH v2] drm/i915/display: Implement wa_14024400148

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 4/22/2025 9:02 PM, Kahola, Mika wrote:
>> -----Original Message-----
>> From: Garg, Nemesa <nemesa.garg@intel.com>
>> Sent: Wednesday, 16 April 2025 18.21
>> To: intel-gfx@lists.freedesktop.org; intel-xe@lists.freedesktop.org; Kahola, Mika
>> <mika.kahola@intel.com>
>> Cc: Garg, Nemesa <nemesa.garg@intel.com>
>> Subject: [PATCH v2] drm/i915/display: Implement wa_14024400148
>>
>> Workaround recommend use polling method
>> for pm_demand to finish as to avoid timeout.
>>
>> v2: Add polling method within pmdemand_wait.
>>      Update error message[Jani]
>>
>> Signed-off-by: Nemesa Garg <nemesa.garg@intel.com>
>> ---
>>   drivers/gpu/drm/i915/display/intel_pmdemand.c | 31 ++++++++++++++++---
>>   1 file changed, 26 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_pmdemand.c
>> b/drivers/gpu/drm/i915/display/intel_pmdemand.c
>> index d22b5469672d..1253376c7654 100644
>> --- a/drivers/gpu/drm/i915/display/intel_pmdemand.c
>> +++ b/drivers/gpu/drm/i915/display/intel_pmdemand.c
>> @@ -478,13 +478,34 @@ static bool intel_pmdemand_req_complete(struct
>> intel_display *display)
>>   		 XELPDP_PMDEMAND_REQ_ENABLE);
>>   }
>>
>> -static void intel_pmdemand_wait(struct intel_display *display)
>> +static void intel_pmdemand_poll(struct intel_display *display)
>>   {
>> -	if (!wait_event_timeout(display->pmdemand.waitqueue,
>> -				intel_pmdemand_req_complete(display),
>> -				msecs_to_jiffies_timeout(10)))
>> +	const unsigned int timeout_ms = 10;
>> +	u32 status;
>> +	int ret;
>> +
>> +	ret = intel_de_wait_custom(display,
>> XELPDP_INITIATE_PMDEMAND_REQUEST(1),
>> +				   XELPDP_PMDEMAND_REQ_ENABLE, 0,
>> +				   50, timeout_ms, &status);
>> +
>> +	if (ret == -ETIMEDOUT)
>>   		drm_err(display->drm,
>> -			"timed out waiting for Punit PM Demand Response\n");
>> +			"timed out waiting for Punit PM Demand Response
>> within %ums (status 0x%08x)\n",
>> +			timeout_ms, status);
>> +}
>> +
>> +static void intel_pmdemand_wait(struct intel_display *display) {
>> +	/* Wa_14024400148 For lnl use polling method */
>> +	if (DISPLAY_VER(display) == 20) {
>> +		intel_pmdemand_poll(display);
>> +	} else {
> Maybe this else branch could be written as its own function as with if branch. Anyway, this might be a topic for follow up patch.
>
> Reviewed-by: Mika Kahola <mika.kahola@intel.com>

Thanks for the patch and review. Pushed to drm-intel-next.

Regards,

Ankit

>
>> +		if (!wait_event_timeout(display->pmdemand.waitqueue,
>> +
>> 	intel_pmdemand_req_complete(display),
>> +					msecs_to_jiffies_timeout(10)))
>> +			drm_err(display->drm,
>> +				"timed out waiting for Punit PM Demand
>> Response\n");
>> +	}
>>   }
>>
>>   /* Required to be programmed during Display Init Sequences. */
>> --
>> 2.25.1