2a8bb9dce7
[ Upstream commit 7beb691f1e6f349c9df3384a85e7a53c5601aaaf ] At the end of a commit, atomic helpers can generate a fake VBLANK event automatically. Originally implemented for writeback connectors, the functionality can be used by any driver and/or hardware without proper VBLANK interrupt. The patch updates the documentation to make this behaviour official: settings struct drm_crtc_state.no_vblank to true enables automatic generation of fake VBLANK events. The new interface drm_dev_has_vblank() returns true if vblanking has been initialized for a device, or false otherwise. Atomic helpers use this function when initializing no_vblank in the CRTC state in drm_atomic_helper_check_modeset(). If vblanking has been initialized for a device, no_blank is disabled. Otherwise it's enabled. Hence, atomic helpers will automatically send out fake VBLANK events with any driver that did not initialize vblanking. v5: * more precise documentation and commit message v4: * replace drm_crtc_has_vblank() with drm_dev_has_vblank() * add drm_dev_has_vblank() in this patch * move driver changes into separate patches v3: * squash all related changes patches into this patch Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Acked-by: Gerd Hoffmann <kraxel@redhat.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20200129120531.6891-2-tzimmermann@suse.de Stable-dep-of: 13fcfcb2a9a4 ("drm/msm/mdp5: Add check for kzalloc") Signed-off-by: Sasha Levin <sashal@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.