set /proc/acpi/video/*/DOS to 4 by default instead of 0
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Medium
|
Andy Whitcroft |
Bug Description
acpi_video_
We want the OS to handle both where possible, so a better default would be to set this to 4, which can be done with a one-liner change:
- return acpi_video_
+ return acpi_video_
The one problem with doing this is that, if the system uses proprietary video drivers, we don't have this brightness control so we need to let the BIOS do it instead. But the kernel default should be optimized for the common case, and we should reset this from 4 to 0 only when the proprietary video drivers need us to (via a udev rule, in the X driver's packaging, etc).
In jaunty and earlier, this bit was set by default for intel and ati chips via the hotkey-setup package, which is now obsolete; so I believe that technically there's a regression here in karmic - but fixing that without breaking other systems that already work as intended would be non-trivial, so we should just fix this in lucid instead.
Matthew Garrett explains the rationale for originally setting this only on intel and ati:
<mjg59> The reason hotkey-setup did that check was because only a subset of drivers supported xrandr 1.2
<mjg59> And for drivers that didn't, it was arguably better to leave it under firmware control than to send the event
<mjg59> In Fedora we've just ended up patching the kernel
<mjg59> In principle that may reduce the functionality on some hardware
<mjg59> But only really stuff running closed drivers
<mjg59> We use 4 by default
ProblemType: Bug
Architecture: amd64
ArecordDevices:
**** List of CAPTURE Hardware Devices ****
card 0: Intel [HDA Intel], device 0: AD198x Analog [AD198x Analog]
Subdevices: 1/1
Subdevice #0: subdevice #0
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/
/dev/snd/pcmC0D0p: vorlon 6116 F...m pulseaudio
Card0.Amixer.info:
Card hw:0 'Intel'/'HDA Intel at 0xee240000 irq 17'
Mixer name : 'Analog Devices AD1981'
Components : 'HDA:11d41981,
Controls : 20
Simple ctrls : 11
Date: Fri Oct 23 03:56:00 2009
DistroRelease: Ubuntu 9.10
HibernationDevice: RESUME=
Lsusb:
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: LENOVO 6371CTO
Package: linux-image-
PccardctlIdent:
Socket 0:
no product info available
PccardctlStatus:
Socket 0:
no card
ProcCmdLine: root=/dev/
ProcEnviron:
PATH=(custom, user)
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcVersionSign
RelatedPackageV
linux-
linux-firmware 1.24
SourcePackage: linux
Uname: Linux 2.6.31-14-generic x86_64
WpaSupplicantLog:
dmi.bios.date: 12/27/2006
dmi.bios.vendor: LENOVO
dmi.bios.version: 7IET23WW (1.04 )
dmi.board.name: 6371CTO
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.
dmi.modalias: dmi:bvnLENOVO:
dmi.product.name: 6371CTO
dmi.product.
dmi.sys.vendor: LENOVO
Related branches
CVE References
tags: | added: kernel-lucid |
Changed in linux (Ubuntu): | |
status: | New → Confirmed |
Changed in linux (Ubuntu): | |
status: | Confirmed → Triaged |
tags: |
added: regression-release removed: regression-potential |
Changed in linux (Ubuntu): | |
assignee: | nobody → Andy Whitcroft (apw) |
status: | Triaged → In Progress |
Changed in linux (Ubuntu): | |
status: | In Progress → Fix Committed |
milestone: | later → lucid-alpha-1 |
Ok, I've spun a patch do this and built test kernels. Could those of you who are affected by this issue test these kernels and report back here. The kernels can be found at the URL below:
http:// people. canonical. com/~apw/ lp458982- karmic/