[PATCH v3 0/9] Add MT8173 Video Decoder Driver

[tiffany.lin@mediatek.com (tiffany lin)]

Hi Hans,

On Fri, 2016-07-08 at 13:44 +0200, Hans Verkuil wrote:
> On 07/07/2016 12:16 PM, tiffany lin wrote:
> > Hi Hans,
> > 
> > 
> > On Wed, 2016-07-06 at 15:19 +0200, Hans Verkuil wrote:
> >> Hi Tiffany,
> >>
> >> I plan to review this patch series on Friday, but one obvious question is
> >> what the reason for these failures is:
> >>
> >>> Input/Output configuration ioctls:
> >>>         test VIDIOC_ENUM/G/S/QUERY_STD: OK (Not Supported)
> >>>         test VIDIOC_ENUM/G/S/QUERY_DV_TIMINGS: OK (Not Supported)
> >>>         test VIDIOC_DV_TIMINGS_CAP: OK (Not Supported)
> >>>         test VIDIOC_G/S_EDID: OK (Not Supported)
> >>>
> >>>         Control ioctls:
> >>>                 test VIDIOC_QUERYCTRL/MENU: OK
> >>>                 fail: ../../../v4l-utils-1.6.0/utils/v4l2-compliance/v4l2-test-controls.cpp(357): g_ctrl returned an error (11)
> >>>                 test VIDIOC_G/S_CTRL: FAIL
> >>>                 fail: ../../../v4l-utils-1.6.0/utils/v4l2-compliance/v4l2-test-controls.cpp(579): g_ext_ctrls returned an error (11)
> >>>                 test VIDIOC_G/S/TRY_EXT_CTRLS: FAIL
> > These fails are because VIDIOC_G_CTRL and VIDIOC_G_EXT_CTRLS return
> > V4L2_CID_MIN_BUFFERS_FOR_CAPTURE only when dirver in MTK_STATE_HEADER
> > state, or it will return EAGAIN.
> > This could help user space get correct value, not default value that may
> > changed base on media content.
> 
> OK, I really don't like this. I also looked what the s5p-mfc-dec driver does (the only other
> driver currently implementing this), and that returns -EINVAL.
> 
> My proposal would be to change this. If this information isn't known yet, why not
> just return 0 as the value? The doc would have to be updated and (preferably) also
> the s5p-mfc-dec driver. I've added Samsung devs to the Cc list, let me know what you
> think.
> 
Got it. We will return 0 as the value instead EAGAIN.

> > 
> >>>                 fail: ../../../v4l-utils-1.6.0/utils/v4l2-compliance/v4l2-test-controls.cpp(721): subscribe event for control 'User Controls' failed
> >>>                 test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: FAIL
> > Driver do not support subscribe event for control 'User Controls' for
> > now.
> > Do we need to support this?
> 
> I don't see why this would fail. It's OK to subscribe to such controls, although
> you'll never get an event.
> 
Got it. I will rerun using latest v4l2-compliance test check this.

> >>>                 test VIDIOC_G/S_JPEGCOMP: OK (Not Supported)
> >>>                 Standard Controls: 2 Private Controls: 0
> >>>
> >>>         Format ioctls:
> >>>                 test VIDIOC_ENUM_FMT/FRAMESIZES/FRAMEINTERVALS: OK
> >>>                 test VIDIOC_G/S_PARM: OK (Not Supported)
> >>>                 test VIDIOC_G_FBUF: OK (Not Supported)
> >>>                 fail: ../../../v4l-utils-1.6.0/utils/v4l2-compliance/v4l2-test-formats.cpp(405): expected EINVAL, but got 11 when getting format for buftype 9
> >>>                 test VIDIOC_G_FMT: FAIL
> > This is because vidioc_vdec_g_fmt only succeed when context is in
> > MTK_STATE_HEADER state, or user space cannot get correct format data
> > using this function.
> 
> Comparing this to s5p-mfc-dec I see that -EINVAL is returned in that case.
> 
> I am not opposed to using EAGAIN in s5p-mfc-dec as well. Marek, Kamil, what is
> your opinion?
> 
> > 
> >>>                 test VIDIOC_TRY_FMT: OK (Not Supported)
> >>>                 test VIDIOC_S_FMT: OK (Not Supported)
> >>>                 test VIDIOC_G_SLICED_VBI_CAP: OK (Not Supported)
> >>>
> >>>         Codec ioctls:
> >>>                 test VIDIOC_(TRY_)ENCODER_CMD: OK (Not Supported)
> >>>                 test VIDIOC_G_ENC_INDEX: OK (Not Supported)
> >>>                 test VIDIOC_(TRY_)DECODER_CMD: OK (Not Supported)
> >>>
> >>>         Buffer ioctls:
> >>>                 test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: OK
> >>>                 fail: ../../../v4l-utils-1.6.0/utils/v4l2-compliance/v4l2-test-buffers.cpp(500): q.has_expbuf(node)
> > Our OUTPUT and CAPTURE queue support both VB2_DMABUF and VB2_MMAP, user
> > space can select which to use in runtime.
> > So our driver default support v4l2_m2m_ioctl_expbuf functionality.
> > In v4l2-compliance test, it will check v4l2_m2m_ioctl_expbuf only valid
> > when node->valid_memorytype is V4L2_MEMORY_MMAP.
> > So when go through node->valid_memorytype is V4L2_MEMORY_DMABUF, it
> > fail.
> 
> valid_memorytype should have both MMAP and DMABUF flags.
> 
> But v4l-utils-1.6.0 is way too old to be certain it isn't some v4l2-compliance bug
> that has since been fixed.
> 
Got it. I will rerun using master branch to check this.

best regards,
Tiffany

> Regards,
> 
> 	Hans
> 
> > 
> > 
> > best regards,
> > Tiffany
> > 
> > 
> > 
> >>>                 test VIDIOC_EXPBUF: FAIL
> >>>
> >>>
> >>> Total: 38, Succeeded: 33, Failed: 5, Warnings: 0
> >>
> >> If it is due to a bug in v4l2-compliance, then let me know and I'll fix it. If not,
> >> then it should be fixed in the driver.
> >>
> >> Frankly, it was the presence of these failures that made me think this patch series
> >> wasn't final. Before a v4l2 driver can be accepted in the kernel, v4l2-compliance must pass.
> >>
> >> Regards,
> >>
> >> 	Hans
> > 
> > 
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