Hi Daniel, On Thu, Sep 28, 2017 at 09:40:35AM +0200, Daniel Vetter wrote: > On Wed, Sep 27, 2017 at 4:01 PM, Steven Price <Steven.Price@xxxxxxx> wrote: > > From: Tu Vuong <tu.vuong@xxxxxxx> > > > > 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. Can you be a bit more specific with "work like this"? You mean all drivers expect mmap-ed calles to have zero offset or the fact that they all zero vm_pgoff therefore ignore the offset? > > > 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 If ignoring the offset is considered uabi, then I agree. Otherwise it looks to me more like a fix, rather than an uabi change. Maybe we should have first a patch warning when vm_pgoff is not zero so that we can find out how many in the userspace use that? Best regards, Liviu > > https://dri.freedesktop.org/docs/drm/gpu/drm-uapi.html#open-source-userspace-requirements > > > Signed-off-by: Tu Vuong <tu.vuong@xxxxxxx> > > Signed-off-by: Steven Price <steven.price@xxxxxxx> > > Reviewed-by: Brian Starkey <brian.starkey@xxxxxxx> > > CC: Brian Starkey <brian.starkey@xxxxxxx> > > CC: Liviu Dudau <Liviu.Dudau@xxxxxxx> > > 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@xxxxxxxxxxxxxxxxxxxxx > > https://lists.freedesktop.org/mailman/listinfo/dri-devel > > > > -- > Daniel Vetter > Software Engineer, Intel Corporation > +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯ _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
