Hi Oleksandr, On 1/29/19 3:04 PM, Oleksandr Andrushchenko wrote:
From: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com>When GEM backing storage is allocated those are normal pages, so there is no point using pgprot_writecombine while mmaping. This fixes mismatch of buffer pages' memory attributes between the frontend and backend which may cause screen artifacts. Fixes: c575b7eeb89f ("drm/xen-front: Add support for Xen PV display frontend") Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com> Suggested-by: Julien Grall <julien.gr...@arm.com> --- drivers/gpu/drm/xen/xen_drm_front_gem.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/xen/xen_drm_front_gem.c b/drivers/gpu/drm/xen/xen_drm_front_gem.c index d303a2e17f5e..9d5c03d7668d 100644 --- a/drivers/gpu/drm/xen/xen_drm_front_gem.c +++ b/drivers/gpu/drm/xen/xen_drm_front_gem.c @@ -235,8 +235,7 @@ static int gem_mmap_obj(struct xen_gem_object *xen_obj, vma->vm_flags &= ~VM_PFNMAP; vma->vm_flags |= VM_MIXEDMAP; vma->vm_pgoff = 0; - vma->vm_page_prot = - pgprot_writecombine(vm_get_page_prot(vma->vm_flags)); + vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
The patch looks good to me. It would be worth expanding the comment a bit before to explain that we overwrite vm_page_prot to use cacheable attribute as required by the Xen ABI.
With the comment updated: Acked-by: Julien Grall <julien.gr...@arm.com> Cheers, -- Julien Grall _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
