Re: [PATCH] drm/xe/client: Check return value of xe_force_wake_get

[Nirmoy Das <nirmoy.das@intel.com>]

Hi Rodrigo,

On 5/28/2024 7:22 PM, Rodrigo Vivi wrote:
> On Tue, May 28, 2024 at 12:11:32PM +0200, Nirmoy Das wrote:
>> xe_force_wake_get() can return error so check it's return value
>> before reading gpu_timestamp value.
>>
>> Fixes: 188ced1e0ff8 ("drm/xe/client: Print runtime to fdinfo")
>> Cc: Lucas De Marchi <lucas.demarchi@intel.com>
>> Signed-off-by: Nirmoy Das <nirmoy.das@intel.com>
>> ---
>>   drivers/gpu/drm/xe/xe_drm_client.c | 6 ++++--
>>   1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_drm_client.c b/drivers/gpu/drm/xe/xe_drm_client.c
>> index 4a19b771e3a0..0c13395ffd34 100644
>> --- a/drivers/gpu/drm/xe/xe_drm_client.c
>> +++ b/drivers/gpu/drm/xe/xe_drm_client.c
>> @@ -245,7 +245,7 @@ static void show_run_ticks(struct drm_printer *p, struct drm_file *file)
>>   	struct xe_gt *gt;
>>   	struct xe_hw_engine *hwe;
>>   	struct xe_exec_queue *q;
>> -	u64 gpu_timestamp;
>> +	u64 gpu_timestamp = 0;
>>   
>>   	xe_pm_runtime_get(xe);
>>   
>> @@ -264,7 +264,9 @@ static void show_run_ticks(struct drm_printer *p, struct drm_file *file)
>>   		if (!hwe)
>>   			continue;
>>   
>> -		xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
>> +		if (xe_force_wake_get(gt_to_fw(gt), XE_FW_GT))
>> +			break;
> worth adding a debug/err msg?

xe_force_wake_get() will throw a drm_notice on error. May be we should 
add a __builtin_return_address() in xe_force_wake_get() to know the 
caller as

the current pattern seems to be to just return early on error ?

>
> but up to you:
>
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Thanks,

Nirmoy

>
>> +
>>   		gpu_timestamp = xe_hw_engine_read_timestamp(hwe);
>>   		xe_force_wake_put(gt_to_fw(gt), XE_FW_GT);
>>   		break;
>> -- 
>> 2.42.0
>>