Re: [PATCH] tests/intel/xe_oa: Ignore other errors when looking for buffer overflow

["Dixit, Ashutosh" <ashutosh.dixit@intel.com>]

On Tue, 20 May 2025 12:52:50 -0700, Umesh Nerlige Ramappa wrote:
>
> Occassionally other error bits will result in EIO and prematurely end
> the buffer-fill test. For this test, ignore other errors.
>
> Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/4565

From CI buglog it looks like, a REPORT_LOST (0x1) status is returned before
BUFFER_OVERFLOW (0x2) status?

Patch generally looks ok, but a question below.


> Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
> ---
>  tests/intel/xe_oa.c | 17 +++++++++++------
>  1 file changed, 11 insertions(+), 6 deletions(-)
>
> diff --git a/tests/intel/xe_oa.c b/tests/intel/xe_oa.c
> index 73841a359daf..2022c5cb3955 100644
> --- a/tests/intel/xe_oa.c
> +++ b/tests/intel/xe_oa.c
> @@ -2520,7 +2520,6 @@ test_buffer_fill(const struct drm_xe_engine_class_instance *hwe)
>	char *buf = malloc(1024);
>	bool overflow_seen;
>	u32 oa_status;
> -	int len;
>
>	igt_debug("oa_period %s\n", pretty_print_oa_period(oa_period));
>	stream_fd = __perf_open(drm_fd, &param, true /* prevent_pm */);
> @@ -2535,16 +2534,22 @@ test_buffer_fill(const struct drm_xe_engine_class_instance *hwe)
>
>	errno = 0;
>	/* Read 0 bytes repeatedly until you see an EIO */
> -	while ((len = read(stream_fd, buf, 0)) == -1 && (errno == EINTR || errno == ENOSPC)) {
> +	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_eq(len, -1);
> -	igt_assert_eq(errno, EIO);
> +	igt_assert(overflow_seen);
>
> -	/* Ensure buffer overflowed */
> +	/* Make sure the buffer overflow is cleared */
> +	read(stream_fd, buf, 0);

How does the buffer overflow status get cleared? We are still doing 0 size reads?

>	oa_status = get_stream_status(stream_fd);
>	overflow_seen = oa_status & DRM_XE_OASTATUS_BUFFER_OVERFLOW;
> -	igt_assert(overflow_seen);
> +	igt_assert_eq(overflow_seen, 0);
>
>	__perf_close(stream_fd);
>  }
> --
> 2.43.0
>

Thanks.
--
Ashutosh