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