Re: [PATCH 15/20] drm/i915/selftests: handle allocation failures

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

On 1/26/22 16:21, Matthew Auld wrote:
> If we have to contend with non-mappable LMEM, then we need to ensure the
> object fits within the mappable portion, like in the selftests, where we
> later try to CPU access the pages. However if it can't then we need to
> gracefully handle this, without throwing an error.
>
> Also it looks like TTM will return -ENOMEM if the object can't be
> placed.

We should probably have a look at why that happens. I thought ttm would 
return -ENOSPC, which we then converted to -ENXIO in i915_ttm_err_to_gem().

/Thomas



> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> ---
>   drivers/gpu/drm/i915/gem/selftests/huge_pages.c      | 2 +-
>   drivers/gpu/drm/i915/selftests/intel_memory_region.c | 8 +++++++-
>   2 files changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
> index 42db9cd30978..3caa178bbd07 100644
> --- a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
> +++ b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
> @@ -1344,7 +1344,7 @@ static int igt_ppgtt_smoke_huge(void *arg)
>   
>   		err = i915_gem_object_pin_pages_unlocked(obj);
>   		if (err) {
> -			if (err == -ENXIO || err == -E2BIG) {
> +			if (err == -ENXIO || err == -E2BIG || err == -ENOMEM) {
>   				i915_gem_object_put(obj);
>   				size >>= 1;
>   				goto try_again;
> diff --git a/drivers/gpu/drm/i915/selftests/intel_memory_region.c b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
> index 04ae29779206..87bff7f83554 100644
> --- a/drivers/gpu/drm/i915/selftests/intel_memory_region.c
> +++ b/drivers/gpu/drm/i915/selftests/intel_memory_region.c
> @@ -822,8 +822,14 @@ static int igt_lmem_create_with_ps(void *arg)
>   
>   		i915_gem_object_lock(obj, NULL);
>   		err = i915_gem_object_pin_pages(obj);
> -		if (err)
> +		if (err) {
> +			if (err == -ENXIO || err == -E2BIG || err == -ENOMEM) {
> +				pr_info("%s not enough lmem for ps(%u) err=%d\n",
> +					__func__, ps, err);
> +				err = 0;
> +			}
>   			goto out_put;
> +		}
>   
>   		daddr = i915_gem_object_get_dma_address(obj, 0);
>   		if (!IS_ALIGNED(daddr, ps)) {