Public bug reported:
After upgrading to Ubuntu 10.04 LTS two years ago some special keys on
my laptop stopped working. They don't send any scan codes or ACPI events
("showkey -s" and "acpi_listen" don't show anything), but they did it on
Ubuntu 9.10 and they still do it on Gentoo with vanilla kernel. I expect
that these keys have to work (to send scan codes and ACPI events) in
newer Ubuntu than 9.10.
It was obvious that problem is in Ubuntu kernel patchset, because the
thing works on vanilla kernel and doesn't work on Ubuntu-patched kernel.
So, I decided to debug patched kernel, found the problem and have
written the patch to fix it. The bug is in the file
"drivers/acpi/video.c" in function acpi_video_bus_start_devices().
There is a line in the function in vanilla kernel:
return acpi_video_bus_DOS(video, 0, 0);
But in Ubuntu-patched kernel it is:
return acpi_video_bus_DOS(video, 0, 1);
The difference is the last argument: there is 0 in vanilla kernel and 1
in Ubuntu kernel.
If I change the last argument to 0 (like in vanilla kernel), my laptop's
problem disappears.
But there should be 1 on other laptops, because setting the last
argument to 1 on other laptops disables automatic display backlight
brightness changing by BIOS when AC power appears/disappears: this
behavior is provided by power manager in userspace and BIOS shouldn't
interfere gnome-power-manager. It is correct on some other laptops, but
my BIOS doesn't touch brightness on AC/DC power switch. However, it
disables Fn+F* keys instead of disabling brightness autoswitch.
So, I think, there should be some settings to set the last parameter to
1 on the most laptops and to 0 on MSI Wind laptops. I'm attaching the
patch. It doesn't change the current behavior by default, but it does if
special kernel command line parameter is used. I hope you will accept
this patch. It doesn't affect anything unless you add kernel command
line parameter "video.brightness_autoswitch_on_power_events=1", but it
fixes the bug on MSI Wind laptop if you add this parameter.
The problem exists in all Ubuntu versions from 10.04 to 12.04 with all
kernels from 2.6.32 to current 3.2.0.
Excuse my poor English.
** Affects: linux (Ubuntu)
Importance: Undecided
Assignee: Maxim Mikityanskiy (maxtram95)
Status: Fix Released
** Tags: acpi bug code kernel key keycode msi scan scancode u100 wind
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/949311
Title:
[PATCH] Fn+F* keys don't work on MSI Wind U100Plus since Ubuntu 10.04
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/949311/+subscriptions
--
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
