mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2026-09-17 09:41:09 +02:00
Ashley Smith
345c5b7cc0
The timeout logic provided by drm_sched leads to races when we try
to suspend it while the drm_sched workqueue queues more jobs. Let's
overhaul the timeout handling in panthor to have our own delayed work
that's resumed/suspended when a group is resumed/suspended. When an
actual timeout occurs, we call drm_sched_fault() to report it
through drm_sched, still. But otherwise, the drm_sched timeout is
disabled (set to MAX_SCHEDULE_TIMEOUT), which leaves us in control of
how we protect modifications on the timer.
One issue seems to be when we call drm_sched_suspend_timeout() from
both queue_run_job() and tick_work() which could lead to races due to
drm_sched_suspend_timeout() not having a lock. Another issue seems to
be in queue_run_job() if the group is not scheduled, we suspend the
timeout again which undoes what drm_sched_job_begin() did when calling
drm_sched_start_timeout(). So the timeout does not reset when a job
is finished.
v2:
- Fix syntax error
v3:
- Split the changes in two commits
v4:
- No changes
v5:
- No changes
v6:
- Fix a NULL deref in group_can_run(), and narrow the group variable
scope to avoid such mistakes in the future
- Add an queue_timeout_is_suspended() helper to clarify things
v7:
- No changes
v8:
- Don't touch drm_gpu_scheduler::timeout in queue_timedout_job()
Fixes: de85488138 ("drm/panthor: Add the scheduler logical block")
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Adrián Larumbe <adrian.larumbe@collabora.com>
Signed-off-by: Ashley Smith <ashley.smith@collabora.com>
Co-developed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Link: https://patch.msgid.link/20251113105734.1520338-2-boris.brezillon@collabora.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.