| Summary: | Intel driver needs a way to enable legacy backlight by default | ||||||
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| Product: | xorg | Reporter: | Brice Goglin <brice.goglin> | ||||
| Component: | Driver/intel | Assignee: | Jesse Barnes <jbarnes> | ||||
| Status: | RESOLVED FIXED | QA Contact: | Xorg Project Team <xorg-team> | ||||
| Severity: | normal | ||||||
| Priority: | medium | CC: | nian.wu | ||||
| Version: | 7.3 (2007.09) | Keywords: | patch | ||||
| Hardware: | Other | ||||||
| OS: | All | ||||||
| URL: | http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=451848 | ||||||
| Whiteboard: | |||||||
| i915 platform: | i915 features: | ||||||
| Bug Depends on: | |||||||
| Bug Blocks: | 13493 | ||||||
| Attachments: |
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Description
Brice Goglin
2007-11-24 01:19:31 UTC
Yeah, changing the default is easy enough. In i830_lvds.c there's some code to detect which method to use, apparently it's getting it wrong on this laptop. So either the detection code is broken or we need a new type of quirk for this machine. Joey, can you confirm what the selected backlight control method is on this machine by default? AFAICT it should be selecting the legacy method for you already, unless you have a kernel backlight interface available. Just run 'xrandr --prop' at startup time to check. Thanks, Jesse (Reply from Joey) it's "combination" on startup Screen 0: minimum 320 x 200, current 1280 x 768, maximum 1280 x 1280 VGA disconnected (normal left inverted right x axis y axis) LVDS connected 1280x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm BACKLIGHT_CONTROL: combination supported: native legacy combination kernel BACKLIGHT: 31250 (0x00007a12) range: (0,31250) 1280x768 59.8*+ 60.0 1152x768 54.8 1024x768 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) TV_FORMAT: NTSC-M supported: NTSC-M NTSC-443 NTSC-J PAL-M PAL-N PAL Aha. I wonder what the best default is... on many machines both the legacy and native registers work, and the combo method tries to use the latter as much as possible. That gives the backlight a nice, large range of brightness. But I guess on some, the native regs are totally ignored, so I wonder if we shouldn't default to legacy if the backlight reg indicates legacy mode... I assume the attached patch works for you? Created attachment 12812 [details]
Use legacy instead of combo backlight method
If we detect that the legacy registers are in use, don't try to use the native regs at all by default.
Yes, Joey says "I've tested it and it works for me". Ok, thanks. I'll push this stuff along with the other backlight fixes. Ok, just pushed the fix for this one. Please open a bug if it's still broken for you. |
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