6d2199868a
Extend vb2_buffer and vb2_queue structs with cache management members. V4L2 UAPI already contains two buffer flags which user-space, supposedly, can use to control buffer cache sync: - V4L2_BUF_FLAG_NO_CACHE_INVALIDATE - V4L2_BUF_FLAG_NO_CACHE_CLEAN None of these, however, do anything at the moment. This patch set is intended to change it. Since user-space cache management hints are supposed to be implemented on a per-buffer basis we need to extend vb2_buffer struct with two new members ->need_cache_sync_on_prepare and ->need_cache_sync_on_finish, which will store corresponding user-space hints. In order to preserve the existing behaviour, user-space cache managements flags will be handled only by those drivers that permit user-space cache hints. That's the purpose of vb2_queue ->allow_cache_hints member. Driver must set ->allow_cache_hints during queue initialisation to enable cache management hints mechanism. Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
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.