On Wed, Sep 27, 2017 at 4:01 PM, Steven Price Steven.Price@arm.com wrote:
From: Tu Vuong tu.vuong@arm.com
When a CMA GEM object is exported via DRM PRIME it should be possible to mmap the object using an offset. However drm_gem_cma_mmap_obj always zeroed vm_pgoff.
No, at least no one ever had run into this. Pretty much all drivers work like this.
Fix this by moving the zeroing of vm_pgoff to drm_gem_cma_mmap (which is only used for non-PRIME mmap) and correct the size parameter in the call to dma_mmap_wc as the offset may not be non-zero.
Since this is an uabi change we need the corresponding patch to upstream open source userspace. Reviewed and all that and ready for acceptance. See
https://dri.freedesktop.org/docs/drm/gpu/drm-uapi.html#open-source-userspace...
Signed-off-by: Tu Vuong tu.vuong@arm.com Signed-off-by: Steven Price steven.price@arm.com Reviewed-by: Brian Starkey brian.starkey@arm.com CC: Brian Starkey brian.starkey@arm.com CC: Liviu Dudau Liviu.Dudau@arm.com
Thanks, Daniel
drivers/gpu/drm/drm_gem_cma_helper.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c index 373e33f22be4..25828b33c5be 100644 --- a/drivers/gpu/drm/drm_gem_cma_helper.c +++ b/drivers/gpu/drm/drm_gem_cma_helper.c @@ -276,15 +276,12 @@ static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj, int ret;
/*
* Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the* vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map* the whole buffer.
* Clear the VM_PFNMAP flag that was set by drm_gem_mmap() */ vma->vm_flags &= ~VM_PFNMAP;
vma->vm_pgoff = 0; ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma_obj->vaddr,cma_obj->paddr, vma->vm_end - vma->vm_start);
cma_obj->paddr, cma_obj->base.size); if (ret) drm_gem_vm_close(vma);@@ -322,6 +319,12 @@ int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma) gem_obj = vma->vm_private_data; cma_obj = to_drm_gem_cma_obj(gem_obj);
/** Set the vm_pgoff (used as a fake buffer offset by DRM) to 0 as we* want to map the whole buffer.*/vma->vm_pgoff = 0;return drm_gem_cma_mmap_obj(cma_obj, vma);} EXPORT_SYMBOL_GPL(drm_gem_cma_mmap); -- 2.11.0 _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel