Re: [PATCH v15 0/6] Media Device Allocator API

[shuah]

On 4/2/19 1:38 AM, Hans Verkuil wrote:
> On 4/2/19 2:40 AM, Shuah Khan wrote:
> > Media Device Allocator API to allows multiple drivers share a media device.
> > This API solves a very common use-case for media devices where one physical
> > device (an USB stick) provides both audio and video. When such media device
> > exposes a standard USB Audio class, a proprietary Video class, two or more
> > independent drivers will share a single physical USB bridge. In such cases,
> > it is necessary to coordinate access to the shared resource.
> >
> > Using this API, drivers can allocate a media device with the shared struct
> > device as the key. Once the media device is allocated by a driver, other
> > drivers can get a reference to it. The media device is released when all
> > the references are released.
> >
> > The primary focus for testing The patch series is making sure media
> > device is released when both drivers release the media device with
> > a series of unbind/binds on both drivers.
> >
> > - both au0828 and snd-usb-aduio as built-in
> > - both au0828 and snd-usb-aduio as modules
> > - au0828 as module and snd-usb-aduio as built-in
> > - au0828 as built-in and snd-usb-aduio as module
> >
> > Test results can be found at:
> >
> > https://docs.google.com/document/d/1RMF8Rwj7xHJEoOx6_K2f-REgZJ63BMeAVEf-CV-0HsM/edit?usp=sharing
>
> Phew, after posting v2 of my patch "au0828: stop video streaming only when last
> user stops" everything now works as it should, including the issue with two VBI
> streams you found.

Awesome. Thanks for taking care of this. Looks good. I tested the
patch and sent Tested-by for it.

> Should I take the selftest patch or will you take that yourself?

Please take this through your pull request. Bundling the test with the
feature will help promote use of this test :)

Please pick up the null pointer dereference fix in bind path when unbind
happens while bind is in progress.

> Let me know so I can make the pull request for this. It's been a long journey
> since the first post on April 9th, 2014: "[RFC PATCH 0/2] managed token devres
> interfaces".

Please send the pull request.

> Almost exactly five years of work!
Amazing. We ended up with a far better solution than the the first patch
series ! Thanks to everybody that helped me with reviews and testing.

thanks,
-- Shuah