[PATCH i-g-t v3 1/2] tests/intel/xe_oa: Clean up buffer-fill test

[Dixit, Ashutosh]

On Thu, 28 Aug 2025 14:49:06 -0700, Umesh Nerlige Ramappa wrote:
>
> Checking for overflow status before enabling the OA buffer is always
> going to return false. Drop the logic.
>
> Move out core buffer overflow check to a helper for reuse by other tests
> when needed.
>
> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
> ---
>  tests/intel/xe_oa.c | 36 ++++++++++++++++++++----------------
>  1 file changed, 20 insertions(+), 16 deletions(-)
>
> diff --git a/tests/intel/xe_oa.c b/tests/intel/xe_oa.c
> index 1826623ab864..3b3cdf9314c2 100644
> --- a/tests/intel/xe_oa.c
> +++ b/tests/intel/xe_oa.c
> @@ -2488,6 +2488,25 @@ test_oa_tlb_invalidate(const struct drm_xe_engine_class_instance *hwe)
>	igt_assert(num_reports2 > 0.95 * num_expected_reports);
>  }
>
> +/*
> + * This is a blocking read trying to read 0 bytes, so it will return ENOSPC
> + * until there is data available. Once the OA buffer overflows, we should see an

What does it mean "until there is data available"? Won't reading 0 bytes
always return ENOSPC? Or you mean until it returns EIO instead of ENOSPC?

> + * EIO with the oevrflow status set.

s/oevrflow/overflow/

> + */
> +static void
> +wait_for_oa_buffer_overflow(int fd, int poll_period_us)
> +{
> +	char buf;
> +
> +	while (-1 == read(fd, &buf, 0)) {
> +		if (errno == EIO &&
> +		    get_stream_status(fd) & DRM_XE_OASTATUS_BUFFER_OVERFLOW)
> +			return;
> +
> +		usleep(poll_period_us);
> +	}
> +}
> +
>  /**
>   * SUBTEST: buffer-fill
>   * Description: Test filling and overflow of OA buffer
> @@ -2526,24 +2545,9 @@ test_buffer_fill(const struct drm_xe_engine_class_instance *hwe)
>	stream_fd = __perf_open(drm_fd, &param, true /* prevent_pm */);
>          set_fd_flags(stream_fd, O_CLOEXEC);
>
> -	/* OA buffer is disabled, we do not expect any error status */
> -	oa_status = get_stream_status(stream_fd);
> -	overflow_seen = oa_status & DRM_XE_OASTATUS_BUFFER_OVERFLOW;
> -	igt_assert_eq(overflow_seen, 0);
> -
>	do_ioctl(stream_fd, DRM_XE_OBSERVATION_IOCTL_ENABLE, 0);
>
> -	/* Read 0 bytes repeatedly until you see an EIO */
> -	while (-1 == read(stream_fd, buf, 0)) {
> -		if (errno == EIO) {
> -			oa_status = get_stream_status(stream_fd);
> -			overflow_seen = oa_status & DRM_XE_OASTATUS_BUFFER_OVERFLOW;
> -			if (overflow_seen)
> -				break;
> -		}
> -		usleep(100);
> -	}
> -	igt_assert(overflow_seen);
> +	wait_for_oa_buffer_overflow(stream_fd, 100);
>
>	/* Make sure the buffer overflow is cleared */
>	read(stream_fd, buf, 0);
> --
> 2.43.0
>

Also the ftrace patch is not merged so maybe add that to the series too.

Otherwise this is:

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