[igt-dev] [i-g-t V2] lib/i915: Handle QUERY_MEMORY_REGIONS on older kernels

[Dixit, Ashutosh]

On Mon, 26 Jul 2021 05:26:36 -0700, Bhanuprakash Modem wrote:
>
> While checking for LMEM support on older kernels with the
> DRM_I915_QUERY_MEMORY_REGIONS, it may fail with EINVAL.
>
> Instead of abort/asserting the test, we must handle this
> case properly.

The patch is fine now. But I would still state clearly in the commit
message what the objective for the patch is. So something like:

"Instead of abort/asserting the test make sure gem_has_lmem remains
functional".

With a suitable commit message this is:

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

> V2:
> * Rebase
>
> Cc: Ashutosh Dixit <ashutosh.dixit at intel.com>
> Cc: Vidya Srinivas <vidya.srinivas at intel.com>
> Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem at intel.com>
> ---
>  lib/i915/intel_memory_region.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/lib/i915/intel_memory_region.c b/lib/i915/intel_memory_region.c
> index e1e210f2c..72e337af3 100644
> --- a/lib/i915/intel_memory_region.c
> +++ b/lib/i915/intel_memory_region.c
> @@ -114,7 +114,7 @@ uint32_t gem_get_batch_size(int fd, uint8_t mem_region_type)
>  struct drm_i915_query_memory_regions *gem_get_query_memory_regions(int fd)
>  {
>	struct drm_i915_query_item item;
> -	struct drm_i915_query_memory_regions *query_info;
> +	struct drm_i915_query_memory_regions *query_info = NULL;
>
>	memset(&item, 0, sizeof(item));
>	item.query_id = DRM_I915_QUERY_MEMORY_REGIONS;
> @@ -123,15 +123,18 @@ struct drm_i915_query_memory_regions *gem_get_query_memory_regions(int fd)
>	 * Any DRM_I915_QUERY_MEMORY_REGIONS specific errors are encoded in the
>	 * item.length, even though the ioctl might still return success.
>	 */
> -	igt_assert_f(item.length > 0,
> -		     "DRM_I915_QUERY_MEMORY_REGIONS failed with %d\n",
> -		     item.length);
> +	if (item.length < 0) {
> +		igt_critical("DRM_I915_QUERY_MEMORY_REGIONS failed with %d\n",
> +			     item.length);
> +		goto out;
> +	}
>
>	query_info = calloc(1, item.length);
>
>	item.data_ptr = to_user_pointer(query_info);
>	i915_query_items(fd, &item, 1);
>
> +out:
>	return query_info;
>  }
>
> @@ -150,6 +153,9 @@ uint8_t gem_get_lmem_region_count(int fd)
>	uint8_t lmem_regions = 0;
>
>	query_info = gem_get_query_memory_regions(fd);
> +	if (!query_info)
> +		goto out;
> +
>	num_regions = query_info->num_regions;
>
>	for (int i = 0; i < num_regions; i++) {
> @@ -158,6 +164,7 @@ uint8_t gem_get_lmem_region_count(int fd)
>	}
>	free(query_info);
>
> +out:
>	return lmem_regions;
>  }
>
> --
> 2.32.0
>