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[WIP] alternative split devices #417

Closed

umlaeute wants to merge 28 commits into develop from feature/split-device

Owner

umlaeute commented Mar 18, 2021

this is just an alternative branch to #359

it's main purpose is to keep the possibility for joined devices, pulling in the changes from #359 every now and then.

this PR is not very actively pursued. it's only a PR to get GitHub-actions (without changing the workflows-configuration)

vicamo and others added 24 commits

March 13, 2021 19:55


          clang-format

1a9445e

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          Merge remote-tracking branch 'vicamo-github/for-upstream/fix-v4l2-com…

d3f7442

…pliance-errors'


          drop hacks for linux<<3

1ca5cce


          mention that linux<<3.0.0 is unsupported

7bace70


          drop VIDIOCGMBUF support

89b476b

V4L1 has been completely removed from kernel since 2.6.39.


          drop useless address-operator from function-tables

790a046


          mod: add output_nr module parameter in parallel with video_nr

c256fb7

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          keep track of both output_nr and capture_nr in IDR

03366a7

With this change, output_nr will be allocated and deallocated as
capture_nr is, but currently saved with no other reference to it.

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          refactor v4l2loopback_lookup

727e625

Since now both output_nr and capture_nr are meaningful, don't return
either of them.

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          cache vdev for latter uses

32cbef3

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          embed struct video_device into v4l2_loopback_device

6c6a6c1

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          set v4l2_loopback_device addr as video_device drvdata instead

c580737

Converting function v4l2loopback_cd2dev and v4l2loopback_getdevice
searches v4l2loopback_index_idr with device number retrieved from
video_device drvdata, but this could be time consuming and creates
unecessary complexity. And since we may need to retrieve
v4l2_loopback_device address from callbacks shared between capture and
output devices, this patch reuses video_device drvdata instead of struct
member offsets.

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          move v4l2_loopback_device->vdev into v4l2_loopback_device->capture

fd056bd

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          move all vdev init procedures into init_vdev

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          fix cap->device_caps may not be defined before v3.3

68616dd

Also use V4L2_CAP_DEVICE_CAPS to detect this instead of hardcoded kernel
version.

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          don't change device state in vidioc_s_fmt_out

eeb0625

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          create a draft output video_device

50e2fcf

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          remove dev->output_nr

210e307

Since we have already instantiated an output video device, use its `num`
field instead.

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          output: add ioctl handlers

babaffe

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          re-implement a separate output device

2f0fb5a

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          prepare to share output/capture entity init

4e0ef85

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          capture: init vb2_queue

6d4a482

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          capture: use fops callback from videobuf2

37c700e

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>


          [wip] reimplement capture entity using videobuf2

ac6439b

Signed-off-by: You-Sheng Yang <vicamo@gmail.com>

umlaeute changed the base branch from main to develop

March 18, 2021 09:39


          Merge branch 'develop' into split-device

8a94f49

Contributor

vicamo commented Mar 19, 2021

Hi, I'd like to point out that struct vb2_queue has a streaming member, and vb2_core_streamon called in vb2_streamon called in vb2_ioctl_streamon would check if it's already in streaming, so it's impossible to share a struct vb2_queue between capture/output because VIDIOC_STREAMON cannot be called twice. So if you'd like to use videobuf2 queue/buf management with joined devices, you'll cannot use these ioctl helper functions, and you cannot use videobuf2 provided fops helper functions directly, either. They check vdev->queue for most calls. You'll need various work-arounds for very detailed implementation level limitations. It's going to be a mess.

umlaeute added 3 commits

March 19, 2021 10:57


          clang-format


          simplified capabilities logic (with only split-devices), setting CAPT…

3a1ab9a

…URE only for capture devices


          set device transfer direction

2e76bec

umlaeute force-pushed the feature/split-device branch from 89d86fc to 2e76bec Compare

March 19, 2021 09:59

Owner Author

umlaeute commented Mar 19, 2021

i think #268 (comment) made it clear that joint devices is not sustainable anyhow.

I'm therefore closing this wip-pr.

the feature/split-devices branch has been rebooted by force-push to be based on your PR #359. (please sync to that as well :-))

(for reference sake, there's another branch that keeps the original content of this PR)

umlaeute closed this

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