Hi, 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. For the entire series, tested with the cedrus driver: Tested-by: Paul Kocialkowski <paul.kocialkowski@xxxxxxxxxxx> Cheers, Paul > 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(-) > -- Paul Kocialkowski, Bootlin (formerly Free Electrons) Embedded Linux and kernel engineering https://bootlin.com
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