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

[Joonyoung Shim <jy0922.shim@samsung.com>]

On 10/13/2015 09:29 PM, Daniel Vetter wrote:
> 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?

Unfortunately not yet, i hope it can be used on real userspace.

Thanks.
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