[PATCH] drm/xe/oa: Ensure that polled read returns latest data

[Umesh Nerlige Ramappa]

On Tue, Feb 11, 2025 at 06:27:01PM -0800, Dixit, Ashutosh wrote:
>On Tue, 11 Feb 2025 17:02:55 -0800, Umesh Nerlige Ramappa wrote:
>>
>> In polled mode, user calls poll() for read data to be available before
>> performing a read(). In the duration between these 2 calls, there may be
>> new data available in the OA buffer. To ensure user reads all available
>> data, check for latest data in the OA buffer in polled read.
>>
>> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
>> ---
>>  drivers/gpu/drm/xe/xe_oa.c | 1 +
>>  1 file changed, 1 insertion(+)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_oa.c b/drivers/gpu/drm/xe/xe_oa.c
>> index fa873f3d0a9d..a692dffcb638 100644
>> --- a/drivers/gpu/drm/xe/xe_oa.c
>> +++ b/drivers/gpu/drm/xe/xe_oa.c
>> @@ -548,6 +548,7 @@ static ssize_t xe_oa_read(struct file *file, char __user *buf,
>>			mutex_unlock(&stream->stream_lock);
>>		} while (!offset && !ret);
>>	} else {
>> +		xe_oa_buffer_check_unlocked(stream);
>>		mutex_lock(&stream->stream_lock);
>>		ret = __xe_oa_read(stream, buf, count, &offset);
>>		mutex_unlock(&stream->stream_lock);
>
>OK, this is what blocking read does when it gets unblocked, so this is
>equivalent to blocking read.
>
>No need to add 'Fixes:' correct?

Right, I don't think a fixes is needed here.

>
>Reviewed-by: Ashutosh Dixit <ashutosh.dixit at intel.com>

Thanks,
Umesh