Ubuntu
linux-source-2.6.22 package

2.6.22-11-generic has two entries in /proc/acpi/video/

Bug #138452 reported by Florin Iucha
8
Affects Status Importance Assigned to Milestone
linux-source-2.6.22 (Ubuntu)
Fix Released
Medium
Ben Collins

Bug Description

Binary package hint: linux-image-2.6.22-11-generic

Using kernel linux-image-2.6.22-10-generic I could not change the backlight intensity on my Thinkpad T60, using the "Power Manager Brightness applet. When I went into /proc/acpi/video, I noticed there are two entries named "VID":

$ ls -li /proc/acpi/video/
total 0
4026532187 dr-xr-xr-x 5 root root 0 2007-09-09 12:42 VID
4026532187 dr-xr-xr-x 5 root root 0 2007-09-09 12:42 VID

When I echoed a number in /proc/acpi/video/VID/LCD0/brightness, it changed the brightness. I don't know if the double entries confused the applet or not.

With linux-image-2.6.22-11-generic, I can change the brightness using the applet, but the two entries are still there.

Tags: cherry-pick
Revision history for this message
Leann Ogasawara (leannogasawara) wrote :

Thank you for taking the time to report this bug and helping to make Ubuntu better. I believe the patch to fix the issue you are seeing was released in the 2.6.23-rc4 mainline kernel. I am re-assigning this bug to the ubuntu kernel-team for their consideration to backport this fix to the 2.6.22 Gutsy kernel. Relevant info provided below:

http://www.kernel.org/pub/linux/kernel/v2.6/testing/ChangeLog-2.6.23-rc4

commit e6d9da1de0f31c57cfe3837b1b4e51c6d96fcd3c
Author: Zhang Rui <email address hidden>
Date: Sat Aug 25 02:23:31 2007 -0400

    ACPI: work around duplicate name "VID" problem on T61

    This can only fix the problem that more than one video bus device
    have the same AML name "VID".
    ie. the proc I/F for the second "VID" video bus device is located under
    /proc/acpi/video/VID1/...

    As this is really rare and the ACPI proc I/F is a legacy feature that
    we are planning to remove.
    We won't provide a generic solution for this problem.

    Signed-off-by: Zhang Rui <email address hidden>
    Signed-off-by: Len Brown <email address hidden>

Changed in linux-source-2.6.22:
assignee: nobody → ubuntu-kernel-team
status: New → Confirmed
Brian Murray (brian-murray)
Changed in linux-source-2.6.22:
importance: Undecided → Medium
status: Confirmed → Triaged
Revision history for this message
Ben Collins (ben-collins) wrote :

ubuntu-gutsy commit-id: 44c5c7b636374afd7c4dcb556e94e78e3c06fedb

Changed in linux-source-2.6.22:
assignee: ubuntu-kernel-team → ben-collins
status: Triaged → Fix Committed
Revision history for this message
Florin Iucha (florin-iucha) wrote :

My original report was mistaken. Even with the latest linux image (linux-image-2.6.22-11-generic 2.6.22-11.33) I can change the LCD brigthness using the gnome applet only when I boot using AC power. If I start the computer and run on batteries, I cannot change the brightness. In the kernel log there is a statement about the "hal acpi add-on" having crashed. I can change the brightness by echoing a value in /proc/acpi/video/VID/LCD0/brightness.

Note that even with the current kernel (2.6.22-11.33), there are still two "VID" entries in /proc/acpi/video.

Also, changing the the current brightness using the applet is not reflected in the /proc entry.

Revision history for this message
Leann Ogasawara (leannogasawara) wrote :

Please note the patch for this was released in 2.6.22-11.34. Marking this 'Fix Released'. You can test the latest kernel release for Gutsy which is version 2.6.22-14.51. Thanks.

Changed in linux-source-2.6.22:
status: Fix Committed → Fix Released
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