c7302f2044
As we need to acquire a mutex to serialise the final intel_wakeref_put, we need to ensure that we are in process context at that time. However, we want to allow operation on the intel_wakeref from inside timer and other hardirq context, which means that need to defer that final put to a workqueue. Inside the final wakeref puts, we are safe to operate in any context, as we are simply marking up the HW and state tracking for the potential sleep. It's only the serialisation with the potential sleeping getting that requires careful wait avoidance. This allows us to retain the immediate processing as before (we only need to sleep over the same races as the current mutex_lock). v2: Add a selftest to ensure we exercise the code while lockdep watches. v3: That test was extremely loud and complained about many things! v4: Not a whale! Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111295 References: https://bugs.freedesktop.org/show_bug.cgi?id=111245 References: https://bugs.freedesktop.org/show_bug.cgi?id=111256 Fixes: 18398904ca9e ("drm/i915: Only recover active engines") Fixes: 51fbd8de87dc ("drm/i915/pmu: Atomically acquire the gt_pm wakeref") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190808202758.10453-1-chris@chris-wilson.co.uk
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 Restructured Text 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.