2696f9010d
TTM takes full control over TTM_PL_SYSTEM placed buffers. This makes driver internal usage of TTM_PL_SYSTEM prone to errors because it requires the drivers to manually handle all interactions between TTM which can swap out those buffers whenever it thinks it's the right thing to do and driver. CPU buffers which need to be fenced and shared with accelerators should be placed in driver specific placements that can explicitly handle CPU/accelerator buffer fencing. Currently, apart, from things silently failing nothing is enforcing that requirement which means that it's easy for drivers and new developers to get this wrong. To avoid the confusion we can document this requirement and clarify the solution. This came up during a discussion on dri-devel: https://lore.kernel.org/dri-devel/232f45e9-8748-1243-09bf-56763e6668b3@amd.com Signed-off-by: Zack Rusin <zackr@vmware.com> Cc: Christian König <christian.koenig@amd.com> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com> Reviewed-by: Christian König <christian.koenig@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20211110145034.487512-1-zackr@vmware.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.