Brightness cannot adjust the backlight on CB+LCD kit

[yanglei]

When use CB+LCD kit to test, we found the brightness applet on statusbar cannot adjust the LCD backlight.

[yanglei (lei-a-yang)]

set the importance as "High" because the brightness applet function fail.

[yanglei (lei-a-yang)]

As Fan tested, we found the even we use Xbacklight to set brightness value by manual, the backlight cannot be adjusted yet.
So I subscribe Alek in.

[alek du (alek-du)]

inuka,
From psb driver the right way to adjust brightness is to set /proc/dri/LVDS/backlight value, but when I set the value, kernel message shows "I2C transfer error". So I guess the psb gfx driver has some problem to set the brightness through I2C, could you confirm that with Tungsten team?

[yanglei (lei-a-yang)]

Todd,
In brightness applet, have we supported /proc/dri/LVDS/backlight entry
to adjust the backlight?

Lei Y

[Inuka Gunawardana (inuka)]

Calvin from UMG provided an app called xproperty. Brightness controls still did not work. However the log showed the following:

Backlightg level = 40

(EE) PSB(0): Probe Address LVDSBLC_B Slave 0x58 failed.

(II) PSB(0): Debug: psbLVDSSetProperty BLC level 40(II) PSB(0): Debug: BLCType=1 Backlightg level = 42

(EE) PSB(0): Probe Address LVDSBLC_B Slave 0x58 failed.

(II) PSB(0): Debug: psbLVDSSetProperty BLC level 42(II) PSB(0): Debug: BLCType=1 Backlightg level = 45

(EE) PSB(0): Probe Address LVDSBLC_B Slave 0x58 failed.

(II) PSB(0): Debug: psbLVDSSetProperty BLC level 45(II) PSB(0): Debug: BLCType=1 Backlightg level = 47

(EE) PSB(0): Probe Address LVDSBLC_B Slave 0x58 failed.

(II) PSB(0): Debug: psbLVDSSetProperty BLC level 47(II) PSB(0): Debug: BLCType=1 Backlightg level = 50

(EE) PSB(0): Probe Address LVDSBLC_B Slave 0x58 failed.

[Inuka Gunawardana (inuka)]

Currently this display does not seem to be supported : This panel is Samsung, Kit L3M21Kpktnste

  Here are the validation panels we support natively in vBIOS:

- 640 x 480 8.4" NEC (NL6448BC26-08D)

- 800 x 480 9" NEC (NL8048BC24-01)

- 1024 x 600 5.61" TMD (LTD056ET0S)

- 1024 x 600 4.8" Samsung (LTS480WS-C01)

- 1024 x 768 15" Samsung (LTX150XG-L01)

- 1280 x 768 7.2" Sharp (LQ072K1LAxx)

- 1280 x 800 15.4" Samsung (LTN154X5-L01)

- 1366 x 768 11.1" TMD (LTD111EXDA)

Other panels can be configured but we do not support them natively.

Attempting to get them to configure it our , get info on how we can configure the display.

[Matthew Garrett (mjg59)]

The PSB driver should be fixed to provide backlight support via the generic /sys/class/backlight API. /proc is entirely the wrong place to have this functionality.

[Inuka Gunawardana (inuka)]

Need to set the display in bios:
simply select ‘1024x600 (Samsung 4.8)’ in BIOS Setup->Chipset->North Bridge
Configuration->Boot Display Configuration->Flat Panel

Used the xproperty utility provided by UMG to test this. http://umd-repo.jf.intel.com/repos/users/inuka/xproperty.tar.gz

However, the status bar applet still does not work. Assigning to Todd.

[yanglei (lei-a-yang)]

inuka,

What's the entry to adjust the backlight, under /proc or /sys?

Lei Y

[yanglei (lei-a-yang)]

Inuka/Alek,

I use /proc/dri/lvds/backlight to adjust the backlight on CB+LCD and it works well.

In general, I think the entry "/sys/class/backlight" is common use for backlight adjustment.
And many 3rd party applications (if want to adjust backlight) will use that entry.
Do we have plan to support this entry?

Lei Y

[alek du (alek-du)]

I agree with mjg59, we should let Gfx team to support /sys/class/backlight standard interface. For the mean time, I could try to fix it.

[alek du (alek-du)]

Fixed. Add sys/class/backlight interface to the driver. tested on D0 CB.

Inuka, please send the patch
http://www.moblin.org/repos/?p=projects/psb-kmd.git;a=blob_plain;f=debian/patches/01backlight.patch;hb=GASTON to Gfx team.

Current build server seems could not build the "GASTON" branch, will update the status once it gets released.

[yanglei (lei-a-yang)]

verified in latest QA image (20080317):
applet brightness use /sys/class/backlight/psblvds/brightness to adjust the backlight.