acpi_video, 5.3-RELEASE, ThinkPad X31?

[Brad Karp]

Greetings, all.

I run 5.3-RELEASE on a ThinkPad X31. Using ACPI, with acpi_video loaded at 
boot time (as verified by kldstat), I find no dmesg output for the acpi_video 
driver; it would seem the driver cannot attach on the X31.

I believe I need acpi_video so that my backlight turns off when I suspend; at 
present, when I transition to state S3, the machine suspends successfully (no 
disk noise; "moon" icon illuminated), and while the image on the display is 
blanked, the power-hungry backlight remains on.

Has anyone with an X31 (or other ThinkPad) found a fix or workaround?

Thanks,
-Brad, bkarp at cs.cmu.edu