Thinkpad A31 backlight stays on during suspend

I also see this behavior on a Thinkpad A31 and Hardy. This, of course, makes suspend rather useless, since the backlight drains the battery so much.

A pointer to information:

http://www.thinkwiki.org/wiki/Problem_with_LCD_backlight_remaining_on_during_ACPI_sleep

I think this may have been fixed for other Thinkpads here: https://bugs.launchpad.net/ubuntu/+bug/199059

A similar fix to #199059 works for me. I enabled the dpms_suspend and radeon_off quirks for my product ID (2652), and now the display turns off.

For reference, here is the page explaining the quirks:

http://people.freedesktop.org/~hughsient/quirk/quirk-suspend-explain.html

Also, I just enabled the dpms_suspend quirk and things seem to work fine. I'm not sure if I get any benefit from the radeon_off quirk

Also, I've sumbitted a patch upstream for my laptop.

Since this bug does not contain any lshal information for identifying the model, and it is discussed in bug 199059 already, I mark this as a duplicate.