[PATCHv9 00/25] Integration of videobuf2 with DMABUF

Mauro Carvalho Chehab mchehab at redhat.com
Wed Oct 10 03:54:18 PDT 2012


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.

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.


More information about the dri-devel mailing list