Ubuntu does not always turn on the backlight properly for the HP Touchsmart tm2 laptop. I have debugged this issue and it seems to be related to the _BCL ACPI function.
The original code is:
Method (OBCL, 0, NotSerialized)
{
BINI ()
If (LEqual (IOSR, One))
{
Return (Package (0x0D)
{
0x64,
0x3C,
0x06,
0x0A,
0x14,
0x1E,
0x28,
0x32,
0x3C,
0x46,
0x50,
0x5A,
0x64
})
}
Else
{
Store (Package (0x0D)
{
0x64,
0x3C,
Zero,
0x0A,
0x14,
0x1E,
0x28,
0x32,
0x3C,
0x46,
0x50,
0x5A,
0x64
}, Local0)
If (LEqual (OSYS, 0x07D6))
{
Return (Package (0x0D)
{
0x64,
0x3C,
0x06,
0x0A,
0x14,
0x1E,
0x28,
0x32,
0x3C,
0x46,
0x50,
0x5A,
0x64
})
}
Return (Local0)
}
}
In this original code, if IOSR isn't 1 and the OS is not Vista, the backlight table will contain 0 for the third entry instead of 6. If Linux sets the backlight to 0, it doesn't seem to be able to turn it on again. I don't know what conditions will cause IOSR to change. Hacking the code to the following seems to fix it and does not affect Windows 7, but I feel that hacking the BIOS is not the best solution and the best long term solution is to make Linux work around the issue:
Method (OBCL, 0, NotSerialized)
{
BINI ()
Return (Package (0x0D)
{
0x64,
0x3C,
0x06,
0x0A,
0x14,
0x1E,
0x28,
0x32,
0x3C,
0x46,
0x50,
0x5A,
0x64
})
}
An unrelated issue is that there is only one _BQC function for the two graphics cards (Intel, ATI), which confuses Linux and makes it unable to correctly determine the current backlight level, which confuses the GNOME backlight widget. I haven't been able to fix this one.
ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: linux-image-2.6.35-24-generic 2.6.35-24.42
Regression: No
Reproducible: Yes
ProcVersionSignature: Ubuntu 2.6.35-24.42-generic 2.6.35.8
Uname: Linux 2.6.35-24-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
AplayDevices: aplay: device_list:235: no soundcards found...
Architecture: amd64
ArecordDevices: arecord: device_list:235: no soundcards found...
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/controlC0', '/dev/snd/hwC0D0', '/dev/snd/pcmC0D0c', '/dev/snd/pcmC0D0p', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
CRDA: Error: [Errno 2] No such file or directory
Date: Tue Jan 4 21:10:33 2011
HibernationDevice: RESUME=UUID=0e1f69a5-b0a9-489b-97d9-f7ab6df34bfb
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007)
MachineType: Hewlett-Packard HP TouchSmart tm2 Notebook PC
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.35-24-generic root=UUID=3a3bdef2-d2b1-42e9-b4f4-8774f733d24a ro quiet splash
ProcEnviron:
PATH=(custom, user)
LANG=en_US.utf8
SHELL=/bin/bash
RelatedPackageVersions: linux-firmware 1.38
SourcePackage: linux
dmi.bios.date: 07/30/2010
dmi.bios.vendor: Insyde
dmi.bios.version: F.12
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: 1486
dmi.board.vendor: Hewlett-Packard
dmi.board.version: 83.1A
dmi.chassis.asset.tag: CNU03037KH
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnInsyde:bvrF.12:bd07/30/2010:svnHewlett-Packard:pnHPTouchSmarttm2NotebookPC:pvr0489200000252A20001220000:rvnHewlett-Packard:rn1486:rvr83.1A:cvnHewlett-Packard:ct10:cvrChassisVersion:
dmi.product.name: HP TouchSmart tm2 Notebook PC
dmi.product.version: 0489200000252A20001220000
dmi.sys.vendor: Hewlett-Packard
Hi Robert,
If you could also please test the latest upstream kernel available that would be great. It will allow additional upstream developers to examine the issue. Refer to https:/
Thanks in advance.
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