[PATCH 0/9] drm/exynos: update codes related with gem

[Daniel Vetter]

On Tue, Oct 13, 2015 at 06:32:53PM +0900, Joonyoung Shim wrote:
> On 10/13/2015 05:37 PM, Joonyoung Shim wrote:
> > On 10/13/2015 05:27 PM, Daniel Vetter wrote:
> >> On Tue, Oct 13, 2015 at 04:00:45PM +0900, Joonyoung Shim wrote:
> >>> Hi,
> >>>
> >>> This patchset is about gem codes update of exynos-drm.
> >>>
> >>> The first and second patches are cleanup to remove useless codes.
> >>> The rest is to support cachable gem allocation.
> >>>
> >>> The exynos-drm uses DMA mapping API to allocate/mmap buffer of gem. If
> >>> it is cachable, does it with DMA_ATTR_NON_CONSISTENT attribute, but
> >>> DMA_ATTR_NON_CONSISTENT isn't supported in DMA mapping API of ARM, so it
> >>> doesn't give any effects.
> >>>
> >>> This patchset introduces new buffer allocation to use
> >>> drm_gem_get/put_pages() instead of DMA mapping API. It will be used
> >>> for the rest except allocation of physically continuous buffer on
> >>> non-iommu, then exynos-drm can support cachable buffer of gem. Also it
> >>> can support physically non-continuous buffer on non-iommu.
> >>>
> >>> EXYNOS_BO_CONTIG flag on iommu is ambiguous because it doesn't care
> >>> whether buffer is continuous physically if iommu is supported. This
> >>> patchset always will use EXYNOS_BO_CONTIG flag on iommu and then can
> >>> mean that the buffer is continuous for device.
> >>>
> >>> There is no user API to control cache coherence for the cpu and device
> >>> about cachable buffer. This patchset introduces two ioctls for cpu
> >>> access of gem object from user. It will be synced properly in order for
> >>> the cpu and device if buffer of gem object is cachable.
> >>
> >> Out of curiosity, where's the userspace part for this work? Usually kernel
> >> abi extensions come with a link to the relevant branch for easier review.
> >> -Daniel
> >>
> > 
> > Right, thanks for point.
> > 
> > I just modified a little bit exynos_fimg2d_test and exynos parts of
> > libdrm to test them as workaround. I will expose it.
> > 
> 
> Please refer follows.
> https://github.com/dofmind/libdrm/commits/exynos
> 
> If fimd2d test program uses cachable gem, it will show cache coherency
> problem, so it adds to use new ioctls to keep cache coherency.

Is there some real userspace too, not just a test/demo app?
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch