aa15c677cc
Don't clip the damage rectangle against the viewport. This only works if the viewport is located at the beginning of the video memory and the video memory doesn't extend the screen (i.e., if there's no overallocation). Fbdev emulation transfers data from write operations into a possible shadow buffer, then into a GEM buffer object, and finally via graphics driver onto the screen. If callers write outside the currently visible area, clipping the damage rectangle against the viewport will loose these updates in the shadow buffer and the fbdev's buffer object will contain stale data. Panning the viewport to the stale area of the buffer will display obsolete data. Instead, mark all written areas as damaged, so that the damage handler updates the buffer object from the shadow buffer for all such areas. The graphics driver's later has the option of clipping the damaged area against the viewport when updating the screen from the buffer object. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220209161617.3553-3-tzimmermann@suse.de
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.