Created attachment 19905 [details] xorg.conf System Environment: -------------------------- platform: 915GM (Thinkpad R52) xserver: 1.5 branch(ec5046ca7565e2364f42606b26159520a73dd207) 2D driver: master branch(87ea531c5dc5b39809395b277c330854aaaaf019) kernel: drm-intel-next (43f7ccc48dd7587983cfe16de578042a7ad3a9b3) lIBDRM : master branch (e47ab7a5081e178bad385ce2e75b01474ea7aa4c) Bug detailed description: -------------------------- on 915GM, the default BACKLIGHT_CONTROL mode is "kernel", and it works well. But when I changed it to "legacy" mode, I changed the BACKLIGHT. It will changed in the information in "xrandr --prop"(shown in following), but the screen doesn't change accordingly and the the actual brightness is always 0. [root@x-915gm drm-intel]# xrandr --prop Screen 0: minimum 320 x 200, current 1024 x 768, maximum 2048 x 2048 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 PANEL_FITTING: center supported: center full_aspect full BACKLIGHT_CONTROL: legacy supported: native legacy combination kernel BACKLIGHT: 254 (0x000000fe) range: (0,255) 1024x768 60.0*+ 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
Created attachment 19906 [details] xorg.0.log
Do you have some reason to expect the legacy mode to work? It won't necessarily be wired up on all platforms, so this might not be a bug...
Based on our discussions offline I'm going to mark this one as notabug.
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