Hi developers, When can't change the LCD brightness in my netboot. It works fine in native netbook's SO (Windows 7 Home Starter). Some informations: cygnus:~# cat /proc/acpi/video/IGD/LCD/brightness <not supported> cygnus:~# ls -l /sys/class/backlight/ total 0 cygnus:~# uname -a Linux cygnus 2.6.34-rc1-git6 #1 SMP Thu Mar 18 13:46:34 BRT 2010 i686 GNU/Linux cygnus:~# cat /etc/debian_version squeeze/sid cygnus:~# lsmod |grep video uvcvideo 44183 0 videodev 26658 1 uvcvideo v4l1_compat 10354 2 uvcvideo,videodev i2c_core 12406 6 i915,drm_kms_helper,drm,i2c_algo_bit,videodev,i2c_i801 video 14805 1 i915 output 1196 1 video usbcore 99096 5 uvcvideo,usb_storage,uhci_hcd,ehci_hcd thermal_sys 9522 4 processor,video,thermal,fan cygnus:~# hwinfo --monitor 26: None 00.0: 10002 LCD Monitor [Created at monitor.95] Unique ID: rdCR.98oPz6MbmnE Hardware Class: monitor Model: "CPT LCD Monitor" Vendor: CPT "CPT" Device: eisa 0x04c4 Resolution: 1024x600@60Hz Size: 222x130 mm Detailed Timings #0: Resolution: 1024x600 Horizontal: 1024 1072 1104 1200 (+48 +80 +176) -hsync Vertical: 600 603 609 625 (+3 +9 +25) -vsync Frequencies: 45.00 MHz, 37.50 kHz, 60.00 Hz Config Status: cfg=new, avail=yes, need=no, active=unknown Other informations are attached. Thanks in advance. Regards, Eriberto - Brazil
Created attachment 25596 [details] More informations.
Created attachment 25597 [details] lshw
Created attachment 25598 [details] acpidump
Created attachment 25599 [details] hwinfo
the backlight is not controlled via ACPI, i.e. no _BCM/_BCL/_BQC methods available. can you change the backlight via xrandr? please attach the full dmesg output of xrandr --verbose
Created attachment 25603 [details] xrandr --verbose
I can't control via xrandr. File attached.
This is not a Linux/ACPI bug because the backlight is not controlled via ACPI. IMO, the problem is that the graphics driver fully rely on the backlight sysfs I/F, and doesn't support the native backlight switching any more. Matthew wrote a patch to fix this, but I don't know the current status.
Zhang, Must I wait a reply from Intel team?
let's wait for Matthew's comments first. :p
Ok Zhang. Thanks a lot for your help. I will wait. Bye!
Opsss... In my original message: 's/When can't change the LCD brightness/I can't change the LCD brightness/' :-)
Created attachment 25804 [details] Native backlight support for Intel This adds native backlight support for Intel. It's against drm-intel, so will probably only apply to 2.6.34-rc kernels. The backlight type support really needs to go upstream before this is mergable.
Dupe of https://bugs.freedesktop.org/show_bug.cgi?id=26664, closing.
https://bugs.freedesktop.org/26664 says: | Should be fixed by building the upstream samsung-laptop drivers. Unfortunately, Eriberto's machine is from Philco, not Samsung.
Missing backlight driver is something for the acpi guys to beat their head against.
From comment #8, 2010: | This is not a Linux/ACPI bug because the backlight is not controlled via ACPI. | | IMO, the problem is that the graphics driver fully rely on the backlight sysfs | I/F, and doesn't support the native backlight switching any more. | | Matthew wrote a patch to fix this, but I don't know the current status. Assigning to platform-driver-x86.