Commit 121ba69f authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/gem: Prevent using pgprot_writecombine() if PAT is not supported 



Let's not try and use PAT attributes for I915_MAP_WC if the CPU doesn't
support PAT.

Fixes: 6056e500 ("drm/i915/gem: Support discontiguous lmem object maps")
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Cc: <stable@vger.kernel.org> # v5.6+
Link: https://patchwork.freedesktop.org/patch/msgid/20200915091417.4086-2-chris@chris-wilson.co.uk
parent 060bb115

drivers/gpu/drm/i915/gem/i915_gem_pages.c

+4 −0
Original line number Diff line number Diff line
@@ -254,6 +254,10 @@ static void *i915_gem_object_map(struct drm_i915_gem_object *obj, 
	if (!i915_gem_object_has_struct_page(obj) && type != I915_MAP_WC)

		return NULL;



	if (GEM_WARN_ON(type == I915_MAP_WC &&

			!static_cpu_has(X86_FEATURE_PAT)))

		return NULL;



	/* A single page can always be kmapped */

	if (n_pte == 1 && type == I915_MAP_WB) {

		struct page *page = sg_page(sgt->sgl);