linux/Documentation/fb
Hans de Goede 83d83bebf4 console/fbcon: Add support for deferred console takeover
Currently fbcon claims fbdevs as soon as they are registered and takes over
the console as soon as the first fbdev gets registered.

This behavior is undesirable in cases where a smooth graphical bootup is
desired, in such cases we typically want the contents of the framebuffer
(typically a vendor logo) to stay in place as is.

The current solution for this problem (on embedded systems) is to not
enable fbcon.

This commit adds a new FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER config option,
which when enabled defers fbcon taking over the console from the dummy
console until the first text is displayed on the console. Together with the
"quiet" kernel commandline option, this allows fbcon to still be used
together with a smooth graphical bootup, having it take over the console as
soon as e.g. an error message is logged.

Note the choice to detect the first console output in the dummycon driver,
rather then handling this entirely inside the fbcon code, was made after
2 failed attempts to handle this entirely inside the fbcon code. The fbcon
code is woven quite tightly into the console code, making this to only
feasible option.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
2018-06-28 15:20:30 +02:00
..
00-INDEX
api.txt
arkfb.txt
aty128fb.txt
cirrusfb.txt
cmap_xfbdev.txt
deferred_io.txt
efifb.txt
ep93xx-fb.txt
fbcon.txt console/fbcon: Add support for deferred console takeover 2018-06-28 15:20:30 +02:00
framebuffer.txt
gxfb.txt
intel810.txt
intelfb.txt
internals.txt
lxfb.txt
matroxfb.txt
metronomefb.txt
modedb.txt
pvr2fb.txt
pxafb.txt
s3fb.txt
sa1100fb.txt
sh7760fb.txt
sisfb.txt
sm501.txt
sm712fb.txt
sstfb.txt
tgafb.txt
tridentfb.txt
udlfb.txt
uvesafb.txt
vesafb.txt
viafb.modes
viafb.txt
vt8623fb.txt