Re: [PATCH v2 15/15] drm/i915/lmem: don't treat small BAR as an error

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

On 2/10/22 13:13, Matthew Auld wrote:
> Just pass along the probed io_size. The backend should be able to
> utilize the entire range here, even if some of it is non-mappable.
>
> It does leave open with what to do with stolen local-memory.
>
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>

Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>


> ---
>   drivers/gpu/drm/i915/gt/intel_region_lmem.c | 6 ++++--
>   1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_region_lmem.c b/drivers/gpu/drm/i915/gt/intel_region_lmem.c
> index 01838b8ce4c7..ad3cf348b4a8 100644
> --- a/drivers/gpu/drm/i915/gt/intel_region_lmem.c
> +++ b/drivers/gpu/drm/i915/gt/intel_region_lmem.c
> @@ -201,6 +201,7 @@ static struct intel_memory_region *setup_lmem(struct intel_gt *gt)
>   	struct intel_memory_region *mem;
>   	resource_size_t min_page_size;
>   	resource_size_t io_start;
> +	resource_size_t io_size;
>   	resource_size_t lmem_size;
>   	int err;
>   
> @@ -211,7 +212,8 @@ static struct intel_memory_region *setup_lmem(struct intel_gt *gt)
>   	lmem_size = intel_uncore_read64(uncore, GEN12_GSMBASE);
>   
>   	io_start = pci_resource_start(pdev, 2);
> -	if (GEM_WARN_ON(lmem_size > pci_resource_len(pdev, 2)))
> +	io_size = min(pci_resource_len(pdev, 2), lmem_size);
> +	if (!io_size)
>   		return ERR_PTR(-ENODEV);
>   
>   	min_page_size = HAS_64K_PAGES(i915) ? I915_GTT_PAGE_SIZE_64K :
> @@ -221,7 +223,7 @@ static struct intel_memory_region *setup_lmem(struct intel_gt *gt)
>   					 lmem_size,
>   					 min_page_size,
>   					 io_start,
> -					 lmem_size,
> +					 io_size,
>   					 INTEL_MEMORY_LOCAL,
>   					 0,
>   					 &intel_region_lmem_ops);