f30e27779d
When userspace requests a video mode parameter value that is not
supported, frame buffer device drivers should round it up to a supported
value, if possible, instead of just rejecting it. This allows
applications to quickly scan for supported video modes.
Currently this rule is not followed for the number of bits per pixel,
causing e.g. "fbset -depth N" to fail, if N is smaller than the current
number of bits per pixel.
Fix this by returning an error only if bits per pixel is too large, and
setting it to the current value otherwise.
See also Documentation/fb/framebuffer.rst, Section 2 (Programmer's View
of /dev/fb*").
Fixes: 865afb11949e5bf4 ("drm/fb-helper: reject any changes to the fbdev")
Cc: stable@vger.kernel.org
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20191230132734.4538-1-geert+renesas@glider.be
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.