d9b42dfab5
DRM clients, such as the fbdev emulation, have their buffer objects mapped by default. Mapping a buffer implicitly prevents its relocation. Hence, the buffer may permanently consume video memory while it's allocated. This is a problem for drivers of low-memory devices, such as ast, mgag200 or older framebuffer hardware, which will then not have enough memory to display other content (e.g., X11). This patch introduces drm_client_buffer_vmap() and _vunmap(). Internal DRM clients can use these functions to unmap and remap buffer objects as needed. There's no reference counting for vmap operations. Callers are expected to either keep buffers mapped (as it is now), or call vmap and vunmap in pairs around code that accesses the mapped memory. v2: * remove several duplicated NULL-pointer checks v3: * style and typo fixes Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Noralf Trønnes <noralf@tronnes.org> Link: https://patchwork.freedesktop.org/patch/315831/ Signed-off-by: Gerd Hoffmann <kraxel@redhat.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.