Messages in this thread | | | Date | Fri, 28 May 2021 11:10:54 +0100 | From | Paul Cercueil <> | Subject | Re: [PATCH] drm: Fix for GEM buffers with write-combine memory |
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Hi Tomi,
Le ven., mai 28 2021 at 08:59:15 +0300, Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> a écrit : > On 28/05/2021 02:03, Paul Cercueil wrote: >> 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> >> Fixes: cf8ccbc72d61 ("drm: Add support for GEM buffers backed by >> non-coherent memory") >> --- >> drivers/gpu/drm/drm_gem_cma_helper.c | 16 ++++++++++------ >> 1 file changed, 10 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c >> b/drivers/gpu/drm/drm_gem_cma_helper.c >> index 235c7a63da2b..4c3772651954 100644 >> --- a/drivers/gpu/drm/drm_gem_cma_helper.c >> +++ b/drivers/gpu/drm/drm_gem_cma_helper.c >> @@ -514,13 +514,17 @@ 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)); >> + } else { >> + ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr, >> + cma_obj->paddr, vma->vm_end - vma->vm_start); >> - ret = dma_mmap_pages(cma_obj->base.dev->dev, >> - vma, vma->vm_end - vma->vm_start, >> - virt_to_page(cma_obj->vaddr)); >> + } >> if (ret) >> drm_gem_vm_close(vma); >> > > Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com> > > and > > Tested-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Thanks, I applied it now.
> > Thanks! > > Btw, the kernel-doc for drm_gem_cma_create doesn't quite match, as it > says wc is always used.
Alright, I'll send a patch later for this one too.
Cheers, -Paul
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