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drm: Fix for GEM buffers with write-combine memory

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The previous commit wrongly assumed that dma_mmap_wc() could be replaced
by pgprot_writecombine() + dma_mmap_pages(). It did work on my setup,
but did not work everywhere.

Use dma_mmap_wc() when the buffer has the write-combine cache attribute,
and dma_mmap_pages() when it has the non-coherent cache attribute.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reported-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Fixes: cf8ccbc72d ("drm: Add support for GEM buffers backed by non-coherent memory")
Link: https://patchwork.freedesktop.org/patch/msgid/20210527230334.151947-1-paul@crapouillou.net
This commit is contained in:
Paul Cercueil 2021-05-28 00:03:34 +01:00
parent 71b970c868
commit 162ba3bd9d
No known key found for this signature in database
GPG Key ID: 73EE6BD2274ABD41
1 changed files with 9 additions and 6 deletions
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15
drivers/gpu/drm/drm_gem_cma_helper.c
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@ -514,13 +514,16 @@ int drm_gem_cma_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
cma_obj = to_drm_gem_cma_obj(obj);
vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
if (!cma_obj->map_noncoherent)
vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
if (cma_obj->map_noncoherent) {
vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
ret = dma_mmap_pages(cma_obj->base.dev->dev,
vma, vma->vm_end - vma->vm_start,
virt_to_page(cma_obj->vaddr));
ret = dma_mmap_pages(cma_obj->base.dev->dev,
vma, vma->vm_end - vma->vm_start,
virt_to_page(cma_obj->vaddr));
} else {
ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,
cma_obj->paddr, vma->vm_end - vma->vm_start);
}
if (ret)
drm_gem_vm_close(vma);