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| author | Robin Murphy <robin.murphy@arm.com> | 2021-10-13 17:36:54 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-02-23 14:03:09 +0300 |
| commit | 02f7d38533ba28429346d6b41ddbbb90355484d1 (patch) | |
| tree | 7cd8cbc383d7a003efba205e28ff546068d1aa57 | |
| parent | 787468ee7a435777521d33399d012fd591ae2f94 (diff) | |
| download | linux-02f7d38533ba28429346d6b41ddbbb90355484d1.tar.xz | |
drm/cma-helper: Set VM_DONTEXPAND for mmap
commit 59f39bfa6553d598cb22f694d45e89547f420d85 upstream.
drm_gem_cma_mmap() cannot assume every implementation of dma_mmap_wc()
will end up calling remap_pfn_range() (which happens to set the relevant
vma flag, among others), so in order to make sure expectations around
VM_DONTEXPAND are met, let it explicitly set the flag like most other
GEM mmap implementations do.
This avoids repeated warnings on a small minority of systems where the
display is behind an IOMMU, and has a simple driver which does not
override drm_gem_cma_default_funcs. Arm hdlcd is an in-tree affected
driver. Out-of-tree, the Apple DCP driver is affected; this fix is
required for DCP to be mainlined.
[Alyssa: Update commit message.]
Fixes: c40069cb7bd6 ("drm: add mmap() to drm_gem_object_funcs")
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211013143654.39031-1-alyssa@rosenzweig.io
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/gpu/drm/drm_gem_cma_helper.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c index 9d05674550a4..6533efa84020 100644 --- a/drivers/gpu/drm/drm_gem_cma_helper.c +++ b/drivers/gpu/drm/drm_gem_cma_helper.c @@ -515,6 +515,7 @@ int drm_gem_cma_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma) */ vma->vm_pgoff -= drm_vma_node_start(&obj->vma_node); vma->vm_flags &= ~VM_PFNMAP; + vma->vm_flags |= VM_DONTEXPAND; cma_obj = to_drm_gem_cma_obj(obj); |