[PATCH 0/2] vt: Simplify console-blanking interface
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From: Thomas Zimmermann <tzimmermann@suse.de>
Date: 2026-10-12 09:41:20
Also in:
linux-serial, lkml, sashiko-reviews
The vt subsystem calls con_blank with what appears to be non-sensical
value. This is because the values and the type of the blank argument
do not match: it mixes up console blank state and monitor DPMS levels
for powersaving. The implmentations of con_blank in various consoles
suffer from the same problem. Update con_blank to a clearer interface.
Also update the consoles.
Patch 1 does a bit of preparation. It converts a boolean parameter
from int to bool, so that its meaning is clearer.
Patch 2 updates con_blank. The callback's blank parameter now controls
blanking in general. The new blank_mode parameter controls the monitor
status and related powersaving.
Tested with vgacon on a SiS 6202 VGA and with fbcon on a Matrox G200
VGA device. The latter also ran fbcon via DRM fbdev emulation. Its easy
to test this with setterm, like this
setterm --blank force # blank
setterm --blank poke # unblank
setterm --blank force --powersave powerdown # blank and turn off monitor
Blanking and unblanking still works in all tested cases.
Thomas Zimmermann (2):
vt: Use boolean as parameter to do_blank_screen() and
do_unblank_screen()
vt: Distinguish between blanking and VESA blank mode in con_blank
drivers/tty/vt/vt.c | 25 ++++++++--------
drivers/tty/vt/vt_ioctl.c | 12 ++++----
drivers/video/console/dummycon.c | 4 +--
drivers/video/console/newport_con.c | 4 +--
drivers/video/console/sticon.c | 4 +--
drivers/video/console/vgacon.c | 44 +++++++++++++++--------------
drivers/video/fbdev/core/fbcon.c | 23 +++++++--------
include/linux/console.h | 9 ++++--
include/linux/vt_kern.h | 5 ++--
9 files changed, 69 insertions(+), 61 deletions(-)
base-commit: b0bd9fb9e92aae2a653efa1d0407daa2aabe99d0
--
2.55.0