[Linaro-mm-sig] [PATCHv9 00/25] Integration of videobuf2 with DMABUF

Kyungmin Park kyungmin.park at samsung.com
Wed Oct 10 04:11:55 PDT 2012

On 10/10/12, Mauro Carvalho Chehab <mchehab at redhat.com> wrote:
> Hi,
> Em Tue, 02 Oct 2012 16:27:11 +0200
> Tomasz Stanislawski <t.stanislaws at samsung.com> escreveu:
>> Hello everyone,
>> This patchset adds support for DMABUF [2] importing and exporting to V4L2
>> stack.
>> v9:
>> - rebase on 3.6
>> - change type for fs to __s32
>> - add support for vb2_ioctl_expbuf
>> - remove patch 'v4l: vb2: add support for DMA_ATTR_NO_KERNEL_MAPPING',
>>   it will be posted as a separate patch
>> - fix typos and style in Documentation (from Hans Verkuil)
>> - only vb2-core and vb2-dma-contig selects DMA_SHARED_BUFFER in Kconfig
>> - use data_offset and length while queueing DMABUF
>> - return the most recently used fd at VIDIOC_DQBUF
>> - use (buffer-type, index, plane) tuple instead of mem_offset
>>   to identify a for exporting (from Hans Verkuil)
>> - support for DMABUF mmap in vb2-dma-contig (from Laurent Pinchart)
>> - add testing alignment of vaddr and size while verifying userptr
>>   against DMA capabilities (from Laurent Pinchart)
>> - substitute VM_DONTDUMP with VM_RESERVED
>> - simplify error handling in vb2_dc_get_dmabuf (from Laurent Pinchart)
> For now, NACK. See below.

Sad news!
It's failed to merge by very poor samsung board support at mainline.

CC arm & samsung mailing list.

Thank you,
Kyungmin Park
> I spent 4 days trying to setup an environment that would allow testing
> DMABUF with video4linux without success (long story, see below). Also,
> Laurent tried the same without any luck, and it seems that it even
> corrupted his test machine.
> Basically Samsung generously donated me two boards that it could be
> used on this test (Origen and SMDK310). None of them actually worked
> with the upstream kernel: patches are needed to avoid OOPSes on
> Origen; both Origen/SMDK310 defconfigs are completely broken, and drivers
> don't even boot if someone tries to use the Kernel's defconfigs.
> Even after spending _days_ trying to figure out the needed .config options
> (as the config files are not easily available), both boards have... issues:
> 	- lack of any display output driver at SMDK310;
> 	- lack of any network driver at Origen: it seems that none of
> the available network options on Origen was upstreamed: no Bluetooth, no
> OTG,
> no Wifi.
> The only test I was able to do (yesterday, late night), the DMABUF caused
> an OOPS at the Origen board. So, for sure it is not ready for upstream.
> It is now, too late for 3.7. I might consider it to 3.8, if something
> can be done to fix the existing issues, and setup a proper setup, using
> the upstream Kernel.
> Regards,
> Mauro
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