d35ca60087
Ensure H2G buffer updates are visible before descriptor tail updates by inserting a barrier between the H2G buffer update and the tail. The barrier is simple wmb() for SMEM and is register write for LMEM. This is needed if more than 1 H2G can be inflight at once. If this barrier is not inserted it is possible the descriptor tail update is scene by the GuC before H2G buffer update which results in the GuC reading a corrupt H2G value. This can bring down the H2G channel among other bad things. Signed-off-by: Matthew Brost <matthew.brost@intel.com> Cc: Michal Wajdeczko <michal.wajdeczko@intel.com> Reviewed-by: John Harrison <John.C.Harrison@Intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20210603051630.2635-16-matthew.brost@intel.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 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.