My display boots black unless I add i915.invert_brightness=1 to my boot parameters (Fedora 20 beta). # lspci -v -s 00:02.0 00:02.0 VGA compatible controller: Intel Corporation 4th Gen Core Processor Integrated Graphics Controller (rev 06) (prog-if 00 [VGA controller]) Subsystem: Hewlett-Packard Company Device 1968 Flags: bus master, fast devsel, latency 0, IRQ 43 Memory at d3000000 (64-bit, non-prefetchable) [size=4M] Memory at c0000000 (64-bit, prefetchable) [size=256M] I/O ports at 6000 [size=64] Expansion ROM at <unassigned> [disabled] Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit- Capabilities: [d0] Power Management version 2 Capabilities: [a4] PCI Advanced Features Kernel driver in use: i915 The backlight hotkeys appear to work as I would expect them, except that I don't press the fn key to activate them, I just press F2 (darker) and F3 (brighter). I'll submit dmesg and /sys/kernel/debug/dri/0/i915_opregion as soon as I can reboot.
Created attachment 87476 [details] dmesg
Created attachment 87477 [details] /sys/kernel/debug/dri/0/i915_opregion
For that second attachment, I was unable to mount debugfs because /sys/kernel/debug was already busy. I just attached the file that was already at /sys/kernel/debug/dri/0/i915_opregion.
Hmm. Wait a minute. Now the system is booting normally without the invert_brightness parm. Investigating further...
Okay, it looks like I just needed to use the hotkeys one time to get a visible screen after boot. The screen brightness gets remembered between boots and it was remembering a black screen until now. The system is working normally now - no invert_brightness needed. (This is really embarrassing.) Please close this bug.
No problem ;-)
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