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f2df84e096
If a CRTC is enabled but not active, and that we're then doing a page
flip on another CRTC, drm_atomic_get_crtc_state will bring the first
CRTC state into the global state, and will make us wait for its vblank
as well, even though that might never occur.
Instead of creating the list of the free channels each time atomic_check
is called, and calling drm_atomic_get_crtc_state to retrieve the
allocated channels, let's create a private state object in the main
atomic state, and use it to store the available channels.
Since vc4 has a semaphore (with a value of 1, so a lock) in its commit
implementation to serialize all the commits, even the nonblocking ones, we
are free from the use-after-free race if two subsequent commits are not ran
in their submission order.
Fixes: 87ebcd42fb ("drm/vc4: crtc: Assign output to channel automatically")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Tested-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Reviewed-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20201120144245.398711-2-maxime@cerno.tech
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.