Bug 14721 - LVDS backlight doesn't come back on after turning off
Summary: LVDS backlight doesn't come back on after turning off
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/intel (show other bugs)
Version: unspecified
Hardware: Other All
: medium major
Assignee: Jesse Barnes
QA Contact: Xorg Project Team
Keywords: NEEDINFO
: 15064 (view as bug list)
Depends on:
Reported: 2008-02-28 12:14 UTC by Jeremy Katz
Modified: 2008-03-28 13:26 UTC (History)
2 users (show)

See Also:
i915 platform:
i915 features:


Description Jeremy Katz 2008-02-28 12:14:18 UTC
After the screensaver kicks in (with version 2.2.1 of the driver) and the LVDS backlight is turned off, having the screen come back doesn't turn the backlight back on.  Doing a randr then kicks it into coming back on.

This is on an 945GM (Thinkpad X60T)
Comment 1 Gordon Jin 2008-03-11 18:53:24 UTC
Please refer to http://www.intellinuxgraphics.org/how_to_report_bug.html to provide more info like kernel/drm version.
Comment 2 Jeremy Katz 2008-03-11 20:17:15 UTC
Happens with Fedora kernels since about a week before the bug was filed, so various 2.6.25-rc-ish kernels.  I'm pretty sure airlied has patched in current git drm, though, on top of that.
Comment 3 WuNian 2008-03-12 01:38:09 UTC
On my GM945(HP 500), I decreased the brightness by typing:
xbacklight -set 20

when screensaver started, I think the backlight is not turned off because the brightness does not change.

After screen comes back, backlight is correct as before screensaver.

My test against FC8(kernel 2.6.23) and upstream tip for all component(2D driver, xserver, Drm).
Comment 4 Michael Fu 2008-03-14 05:57:25 UTC
Jeremy, please provide more detailed description of your environment, as we can't reproduce your issue here in our environment. Following the requirements mentioned in comment# 1 would be good enough... thanks.
Comment 5 Jesse Barnes 2008-03-18 18:36:06 UTC
Jeremy, a few more things:
  - 'xrandr --prop'
  - results when ACPI 'video' kernel driver is loaded
  - results when thinkpad_acpi is loaded
Comment 6 Jeremy Katz 2008-03-25 08:05:05 UTC
thinkpad_acpi gets loaded by dmi, so it was loaded.  video wasn't but I tried it at one point and it didn't make a difference.  

[katzj@aglarond Desktop]$ xrandr --prop
Screen 0: minimum 320 x 200, current 1024 x 768, maximum 1024 x 1024
VGA disconnected (normal left inverted right x axis y axis)
LVDS connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
        BACKLIGHT_CONTROL: combination
                supported: native       legacy       combination  kernel      
        BACKLIGHT: 18937 (0x000049f9) range:  (0,18937)
   1024x768       57.6*+   85.0     75.0     70.1     60.0  
   832x624        74.6  
   800x600        85.1     72.2     75.0     60.3     56.2  
   640x480        85.0     72.8     75.0     59.9  
   720x400        85.0  
   640x400        85.1  
   640x350        85.1  
TV disconnected (normal left inverted right x axis y axis)
        BOTTOM: 37 (0x00000025) range:  (0,100)
        RIGHT: 46 (0x0000002e) range:  (0,100)
        TOP: 36 (0x00000024) range:  (0,100)
        LEFT: 54 (0x00000036) range:  (0,100)
                supported: NTSC-M       NTSC-443     NTSC-J       PAL-M       
                           PAL-N        PAL         

But note that that run is after building the driver with th ebacklight patch you posted to the xorg list last week.  And said patch fixes things for me.
Comment 7 Jesse Barnes 2008-03-25 15:16:14 UTC
*** Bug 15064 has been marked as a duplicate of this bug. ***
Comment 8 Jesse Barnes 2008-03-28 13:26:05 UTC
Fixed in 1450acd046d47e1739a3ffbd146c73ad2974a935.

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