Daniel Vetter 39aead8373 fbcon: Disable accelerated scrolling ... So ever since syzbot discovered fbcon, we have solid proof that it's full of bugs. And often the solution is to just delete code and remove features, e.g. 50145474f6 ("fbcon: remove soft scrollback code"). Now the problem is that most modern-ish drivers really only treat fbcon as an dumb kernel console until userspace takes over, and Oops printer for some emergencies. Looking at drm drivers and the basic vesa/efi fbdev drivers shows that only 3 drivers support any kind of acceleration: - nouveau, seems to be enabled by default - omapdrm, when a DMM remapper exists using remapper rewriting for y/xpanning - gma500, but that is getting deleted now for the GTT remapper trick, and the accelerated copyarea never set the FBINFO_HWACCEL_COPYAREA flag, so unused (and could be deleted already I think). No other driver supportes accelerated fbcon. And fbcon is the only user of this accel code (it's not exposed as uapi through ioctls), which means we could garbage collect fairly enormous amounts of code if we kill this. Plus because syzbot only runs on virtual hardware, and none of the drivers for that have acceleration, we'd remove a huge gap in testing. And there's no other even remotely comprehensive testing aside from syzbot. This patch here just disables the acceleration code by always redrawing when scrolling. The plan is that once this has been merged for well over a year in released kernels, we can start to go around and delete a lot of code. v2: - Drop a few more unused local variables, somehow I missed the compiler warnings (Sam) - Fix typo in comment (Jiri) - add a todo entry for the cleanup (Thomas) v3: Remove more unused variables (0day) Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Sam Ravnborg <sam@ravnborg.org> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ben Skeggs <bskeggs@redhat.com> Cc: nouveau@lists.freedesktop.org Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Peilin Ye <yepeilin.cs@gmail.com> Cc: George Kennedy <george.kennedy@oracle.com> Cc: Nathan Chancellor <natechancellor@gmail.com> Cc: Peter Rosin <peda@axentia.se> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20201029132229.4068359-1-daniel.vetter@ffwll.ch		2020-11-17 11:00:29 +01:00
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aty	video: use kobj_to_dev()	2020-10-16 22:59:00 +02:00
core	fbcon: Disable accelerated scrolling	2020-11-17 11:00:29 +01:00
geode
i810
intelfb
kyro
matrox	matroxfb: avoid -Warray-bounds warning	2020-10-27 07:56:19 +01:00
mb862xx
mmp
nvidia	fbdev: nvidia: use for_each_child_of_node() macro	2020-10-16 23:43:41 +02:00
omap
omap2	omapfb: connector-dvi: simplify the return expression of dvic_connect()	2020-10-17 08:10:10 +02:00
riva	video: fbdev: riva: remove some unused varibles	2020-11-09 08:28:29 +01:00
savage
sis	video: fbdev: sis: remove unneeded semicolon	2020-10-17 08:22:32 +02:00
vermilion
via	Merge drm/drm-next into drm-misc-next	2020-09-14 18:11:40 +02:00
68328fb.c
acornfb.c
acornfb.h
amba-clcd.c	Partially revert "video: fbdev: amba-clcd: Retire elder CLCD driver"	2020-09-30 16:37:39 +02:00
amifb.c
arcfb.c
arkfb.c
asiliantfb.c
atafb.c	fbdev/atafb: Remove unused extern variables	2020-10-28 19:40:11 +01:00
atafb.h
atafb_iplan2p2.c
atafb_iplan2p4.c
atafb_iplan2p8.c
atafb_mfb.c
atafb_utils.h
atmel_lcdfb.c	video: fbdev: atmel_lcdfb: fix return error code in atmel_lcdfb_of_init()	2020-11-17 08:47:15 +01:00
au1100fb.c
au1100fb.h
au1200fb.c
au1200fb.h
broadsheetfb.c
bt431.h
bt455.h
bw2.c
c2p.h
c2p_core.h
c2p_iplan2.c
c2p_planar.c
carminefb.c
carminefb.h
carminefb_regs.h
cg3.c
cg6.c
cg14.c
chipsfb.c
cirrusfb.c	video: fbdev: fix divide error in fbcon_switch	2020-10-23 08:47:30 +02:00
clps711x-fb.c
cobalt_lcdfb.c
controlfb.c
controlfb.h
cyber2000fb.c
cyber2000fb.h
da8xx-fb.c
dnfb.c
edid.h
efifb.c
ep93xx-fb.c
ffb.c
fm2fb.c
fsl-diu-fb.c	video: fbdev: fsl-diu-fb: remove unneeded variable 'res'	2020-10-17 08:23:14 +02:00
g364fb.c
gbefb.c
goldfishfb.c
grvga.c
gxt4500.c
hecubafb.c
hgafb.c
hitfb.c
hpfb.c
hyperv_fb.c	hyperv_fb: Update screen_info after removing old framebuffer	2020-10-14 17:05:26 +02:00
i740_reg.h
i740fb.c
imsttfb.c
imxfb.c
Kconfig	drm next for 5.10-rc1	2020-10-15 10:46:16 -07:00
leo.c
macfb.c
macmodes.c
macmodes.h
Makefile	drm next for 5.10-rc1	2020-10-15 10:46:16 -07:00
maxinefb.c
metronomefb.c
mx3fb.c	fbdev: mx3fb: remove unused variable 'irq'	2020-09-24 22:06:16 +02:00
n411.c
neofb.c
ocfb.c
offb.c
p9100.c
platinumfb.c
platinumfb.h
pm2fb.c
pm3fb.c
pmag-aa-fb.c
pmag-ba-fb.c
pmagb-b-fb.c
ps3fb.c
pvr2fb.c
pxa3xx-gcu.c
pxa3xx-gcu.h
pxa168fb.c
pxa168fb.h
pxafb.c
pxafb.h
q40fb.c
s1d13xxxfb.c
s3c-fb.c
s3c2410fb-regs-lcd.h
s3c2410fb.c
s3c2410fb.h
s3fb.c
sa1100fb.c
sa1100fb.h
sbuslib.c	fbdev: sbuslib: remove compat_alloc_user_space usage	2020-09-25 16:34:50 +02:00
sbuslib.h
sh7760fb.c
sh_mobile_lcdcfb.c	fbdev/sh_mobile: Drop unused include	2020-11-01 10:29:04 +01:00
sh_mobile_lcdcfb.h
simplefb.c
skeletonfb.c
sm501fb.c
sm712.h
sm712fb.c
smscufx.c
ssd1307fb.c
sstfb.c
sticore.h	parisc/sticon: Add user font support	2020-10-15 08:12:59 +02:00
stifb.c
sunxvr500.c
sunxvr1000.c
sunxvr2500.c
tcx.c
tdfxfb.c
tgafb.c
tmiofb.c
tridentfb.c
udlfb.c
uvesafb.c
valkyriefb.c
valkyriefb.h
vesafb.c
vfb.c
vga16fb.c	Merge drm/drm-next into drm-misc-next	2020-09-14 18:11:40 +02:00
vt8500lcdfb.c
vt8500lcdfb.h
vt8623fb.c
w100fb.c
w100fb.h
wm8505fb.c
wm8505fb_regs.h
wmt_ge_rops.c
wmt_ge_rops.h
xen-fbfront.c
xilinxfb.c