The patch below does not apply to the 5.3-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From bdae33b8b82bb379a5b11040b0b37df25c7871c9 Mon Sep 17 00:00:00 2001
From: Chris Wilson chris@chris-wilson.co.uk Date: Thu, 18 Jul 2019 15:54:05 +0100 Subject: [PATCH] drm/i915: Use maximum write flush for pwrite_gtt MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit
As recently disovered by forcing big-core (!llc) machines to use the GTT paths, we need our full GTT write flush before manipulating the GTT PTE or else the writes may be directed to the wrong page.
Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: Matthew Auld matthew.william.auld@gmail.com Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: stable@vger.kernel.org Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20190718145407.21352-2-chris@c...
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index fed0bc421a55..c6ba350e6e4f 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -610,7 +610,8 @@ i915_gem_gtt_pwrite_fast(struct drm_i915_gem_object *obj, unsigned int page_length = PAGE_SIZE - page_offset; page_length = remain < page_length ? remain : page_length; if (node.allocated) { - wmb(); /* flush the write before we modify the GGTT */ + /* flush the write before we modify the GGTT */ + intel_gt_flush_ggtt_writes(ggtt->vm.gt); ggtt->vm.insert_page(&ggtt->vm, i915_gem_object_get_dma_address(obj, offset >> PAGE_SHIFT), node.start, I915_CACHE_NONE, 0); @@ -639,8 +640,8 @@ i915_gem_gtt_pwrite_fast(struct drm_i915_gem_object *obj, i915_gem_object_unlock_fence(obj, fence); out_unpin: mutex_lock(&i915->drm.struct_mutex); + intel_gt_flush_ggtt_writes(ggtt->vm.gt); if (node.allocated) { - wmb(); ggtt->vm.clear_range(&ggtt->vm, node.start, node.size); remove_mappable_node(&node); } else {