Hi,

On Mon, 2018-11-12 at 18:05 -0300, Ezequiel Garcia wrote:
> On Mon, 12 Nov 2018 at 13:52, Paul Kocialkowski
> <paul.kocialkowski@bootlin.com> wrote:
> > Hi,
> > 
> > On Sun, 2018-11-11 at 18:26 -0300, Ezequiel Garcia wrote:
> > > On Thu, 2018-10-18 at 15:02 -0300, Ezequiel Garcia wrote:
> > > > This series goal is to avoid drivers from having ad-hoc code
> > > > to call .device_run in non-atomic context. Currently, .device_run
> > > > can be called via v4l2_m2m_job_finish(), not only running
> > > > in interrupt context, but also creating a nasty re-entrant
> > > > path into mem2mem drivers.
> > > > 
> > > > The proposed solution is to add a per-device worker that is scheduled
> > > > by v4l2_m2m_job_finish, which replaces drivers having a threaded interrupt
> > > > or similar.
> > > > 
> > > > This change allows v4l2_m2m_job_finish() to be called in interrupt
> > > > context, separating .device_run and v4l2_m2m_job_finish() contexts.
> > > > 
> > > > It's worth mentioning that v4l2_m2m_cancel_job() doesn't need
> > > > to flush or cancel the new worker, because the job_spinlock
> > > > synchronizes both and also because the core prevents simultaneous
> > > > jobs. Either v4l2_m2m_cancel_job() will wait for the worker, or the
> > > > worker will be unable to run a new job.
> > > > 
> > > > Patches apply on top of Request API and the Cedrus VPU
> > > > driver.
> > > > 
> > > > Tested with cedrus driver using v4l2-request-test and
> > > > vicodec driver using gstreamer.
> > > > 
> > > > Ezequiel Garcia (4):
> > > >   mem2mem: Require capture and output mutexes to match
> > > >   v4l2-ioctl.c: Simplify locking for m2m devices
> > > >   v4l2-mem2mem: Avoid calling .device_run in v4l2_m2m_job_finish
> > > >   media: cedrus: Get rid of interrupt bottom-half
> > > > 
> > > > Sakari Ailus (1):
> > > >   v4l2-mem2mem: Simplify exiting the function in __v4l2_m2m_try_schedule
> > > > 
> > > >  drivers/media/v4l2-core/v4l2-ioctl.c          | 47 +------------
> > > >  drivers/media/v4l2-core/v4l2-mem2mem.c        | 66 ++++++++++++-------
> > > >  .../staging/media/sunxi/cedrus/cedrus_hw.c    | 26 ++------
> > > >  3 files changed, 51 insertions(+), 88 deletions(-)
> > > > 
> > > 
> > > Hans, Maxime:
> > > 
> > > Any feedback for this?
> > 
> > I just tested the whole series with the cedrus driver and everything
> > looks good!
> > 
> 
> Good! So this means we can add a Tested-by for the entire series?

Definitely, I just sent the tested-by line on the cover letter!

> > Removing the interrupt bottom-half in favor of a workqueue in the core
> > seems like a good way to simplify m2m driver development by avoiding
> > per-driver workqueues or threaded irqs.
> > 
> 
> Thanks for the test!

Cheers,

Paul

-- 
Paul Kocialkowski, Bootlin (formerly Free Electrons)
Embedded Linux and kernel engineering
https://bootlin.com