Commit 34dbb848d5 ("media: mem2mem: Remove excessive try_run call")
removed a redundant call to v4l2_m2m_try_run but instead introduced
a bug. Consider the following case:
1) Context A schedules, queues and runs job A.
2) While the m2m device is running, context B schedules
and queues job B. Job B cannot run, because it has to
wait for job A.
3) Job A completes, calls v4l2_m2m_job_finish, and tries
to queue a job for context A, but since the context is
empty it won't do anything.
In this scenario, queued job B will never run. Fix this by calling
v4l2_m2m_try_run from v4l2_m2m_try_schedule.
While here, add more documentation to these functions.
Fixes: 34dbb848d5 ("media: mem2mem: Remove excessive try_run call")
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
[hans.verkuil@cisco.com: split >80 cols line]
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
9db3bbf58b