8d52e44780
If we avoid cleaning up the old state immediately in intel_atomic_commit_tail() and defer it to a second task, we can avoid taking heavily contended locks when the caller is ready to procede. Subsequent modesets will wait for the cleanup operation (either directly via the ordered modeset wq or indirectly through the atomic helperr) which keeps the number of inflight cleanup tasks in check. As an example, during reset an immediate modeset is performed to disable the displays before the HW is reset, which must avoid struct_mutex to avoid recursion. Moving the cleanup to a separate task, defers acquiring the struct_mutex to after the GPU is running again, allowing it to complete. Even in a few patches time (optimist!) when we no longer require struct_mutex to unpin the framebuffers, it will still be good practice to minimise the number of contention points along reset. The mutex dependency still exists (as one modeset flushes the other), but in the short term it resolves the deadlock for simple reset cases. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101600 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Link: https://patchwork.freedesktop.org/patch/msgid/20180623103951.23889-1-chris@chris-wilson.co.uk Acked-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.