Package: hotkey-setup
Version: 0.1-17.1
Severity: normal
When Xwindows' DPMS (display power mamangement) kicks in and
turns the display off to save power, thinkpad-keys incorrectly sees this
as a change in display brightness, and generates a KEY_BRIGHTNESSUP
event. This event resets the idle timer, cancelling DPMS mode and
turning the display back on. Rinse, repeat...
Looking at the source code, my *guess* is that the
'brightness_moved' bit is being changed by the ACPI BIOS when DPMS is
engaged, but thinkpad-keys doesn't cross-check that the 'brightness'
field actually changed value, and generates a KEY_BRIGHTNESSUP event as
a result.
To reproduce:
- Launch X.
- Force DPMS to engage:
bash$ xset dpms force standby
- The display will briefly blank, then re-activate. This is due
to the event generated by thinkpad-keys.
- Kill thinkpad-keys.
bash# kill `pidof thinkpad-keys`
- Force DPMS to engage again.
- The display remains blanked.
You can actually see this happen using the 'evtest' program and
running it against the /dev/input/event* node that carries the events
generated by thinkpad-keys. A KEY_BRIGHTNESSUP event will appear when
DPMS engages.
Note that DPMS blanking is distinct from "screensaver" blanking,
the latter of which usually happens before DPMS is engaged. Both forms
of blanking are controlled by 'xset' One way to (quickly) illustrate
that it's DPMS activity that's confusing thinkpad-keys is to set the
various blanking timeouts to brief intervals:
bash$ xset s 10 10
bash$ xset dpms 20 30 40
This sets the "screensaver" timeout to ten seconds, DPMS Standby
to 20 seconds, DPMS Suspend to 30 seconds, and DPMS Off to 40 seconds.
After ten seconds, the display will enter "screensaver"
blanking. Ten seconds after that, DPMS Standby will be engaged, causing
thinkpad-keys to emit KEY_BRIGHTNESSUP, and the display will wake back
up again.
Please investigate. You may wish to coordinate your solution
with the author(s) of the thinkpad_acpi (nee ibm_acpi) kernel module.
Thanks,
Schwab
-- System Information:
Debian Release: lenny/sid
APT prefers unstable
APT policy: (500, 'unstable'), (500, 'testing'), (500, 'stable')
Architecture: i386 (i686)
Kernel: Linux 2.6.22 (SMP w/2 CPU cores; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash
Versions of packages hotkey-setup depends on:
ii dmidecode 2.9-1 Dump Desktop Management Interface
hotkey-setup recommends no packages.
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