Created attachment 43712 [details] dmesg output I am unable to regulate brightness with 2.6.37-git14. The same issue occurrs with 2.6.37-git11 too while 2.6.37-git9 and 2.6.37-git10 don't. The four configuation files are almost the same except for some minor changes generated by `make oldconfig'. Here is `lspci | grep -i video': 02:00.0 VGA compatible controller: ATI Technologies Inc M92 [Mobility Radeon HD 4500 Series]
how do you control the backlight? hotkeys? or sysfs I/F? does changing /sys/class/backlight/acpi_video0/brightness work for you?
When the backlight control function is disabled, the /sys/class/backlight/ directory is empty. Here is a snippet extracted from `dmesg': pnp 00:06: [io 0x0070-0x0077] pnp 00:06: Plug and Play ACPI device, IDs PNP0b00 (active) pnp 00:07: [io 0x0060] pnp 00:07: [io 0x0064] pnp 00:07: [irq 1] pnp 00:07: Plug and Play ACPI device, IDs PNP0303 (active) pnp 00:08: [irq 12] pnp 00:08: Plug and Play ACPI device, IDs DLL0404 PNP0f13 (active) pnp 00:09: [irq 23] pnp 00:09: Plug and Play ACPI device, IDs SMO8800 (active) ACPI Exception: AE_ERROR, Returned by Handler for [PCI_Config] (20101209/evregion-474) ACPI Error: Method parse/execution failed [\_SB_.PCI0.PDRC._CRS] (Node ffff880133a93a50), AE_ERROR (20101209/psparse-537) ACPI Error: Method execution failed [\_SB_.PCI0.PDRC._CRS] (Node ffff880133a93a50), AE_ERROR (20101209/uteval-103) pnp 00:0a: can't evaluate _CRS: 1 system 00:0a: Plug and Play ACPI device, IDs PNP0c02 (active) pnp 00:0b: [bus ff] pnp 00:0b: Plug and Play ACPI device, IDs PNP0a03 (active) pnp: PnP ACPI: found 12 devices ACPI: ACPI bus type pnp unregistered
I have compiled a 2.6.38-rc2-git3 kernel while this issue remains.
does this patch help? https://patchwork.kernel.org/patch/499221/
This patch works with 2.6.38-rc4. Thanks!
*** This bug has been marked as a duplicate of bug 27702 ***