Re: [Intel-gfx] [PATCH] drm/i915: Do not set cache_dirty for DGFX

["Das, Nirmoy" <nirmoy.das@linux.intel.com>]

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On 11/2/2022 6:14 AM, Niranjana Vishwanathapura wrote:
> Currently on DG1, which do not have LLC, we hit the below
> warning while rebinding an userptr invalidated object.
>
> WARNING: CPU: 4 PID: 13008 at drivers/gpu/drm/i915/gem/i915_gem_pages.c:34 __i915_gem_object_set_pages+0x296/0x2d0 [i915]
> ...
> RIP: 0010:__i915_gem_object_set_pages+0x296/0x2d0 [i915]
> ...
> Call Trace:
>   <TASK>
>   i915_gem_userptr_get_pages+0x175/0x1a0 [i915]
>   ____i915_gem_object_get_pages+0x32/0xb0 [i915]
>   i915_gem_object_userptr_submit_init+0x286/0x470 [i915]
>   eb_lookup_vmas+0x2ff/0xcf0 [i915]
>   ? __intel_wakeref_get_first+0x55/0xb0 [i915]
>   i915_gem_do_execbuffer+0x785/0x21d0 [i915]
>   i915_gem_execbuffer2_ioctl+0xe7/0x3d0 [i915]
>
> We shouldn't be setting the obj->cache_dirty for DGFX,
> fix it.

With Fixes: |d70af57944 |("drm/i915/shmem: ensure flush during swap-in 
on non-LLC")

Acked-by: Nirmoy Das <nirmoy.das@intel.com>

> Suggested-by: Matthew Auld<matthew.auld@intel.com>
> Reported-by: Niranjana Vishwanathapura<niranjana.vishwanathapura@intel.com>
> Signed-off-by: Niranjana Vishwanathapura<niranjana.vishwanathapura@intel.com>
> ---
>   drivers/gpu/drm/i915/gem/i915_gem_shmem.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> index 11125c32dd35..2f7804492cd5 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_shmem.c
> @@ -369,14 +369,14 @@ __i915_gem_object_release_shmem(struct drm_i915_gem_object *obj,
>   
>   	__start_cpu_write(obj);
>   	/*
> -	 * On non-LLC platforms, force the flush-on-acquire if this is ever
> +	 * On non-LLC igfx platforms, force the flush-on-acquire if this is ever
>   	 * swapped-in. Our async flush path is not trust worthy enough yet(and
>   	 * happens in the wrong order), and with some tricks it's conceivable
>   	 * for userspace to change the cache-level to I915_CACHE_NONE after the
>   	 * pages are swapped-in, and since execbuf binds the object before doing
>   	 * the async flush, we have a race window.
>   	 */
> -	if (!HAS_LLC(i915))
> +	if (!HAS_LLC(i915) && !IS_DGFX(i915))
>   		obj->cache_dirty = true;
>   }
>   

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