As advised on dri-devel@lists.freedesktop.org by Jani Nikula I would like to report that my Lenovo IdeaPad requires i915.invert_brightness=1 kernel parameter to not dim screen after boot. According to Jani 'this is highly unlikely to be the case on' my hardware. I use dual display with Samsung SyncMaster 931BF, latest kernel (3.17.0-rc3+) and Debian Jessie/Sid. [12:39:34] pietrushnic:~ $ lspci -s 00:02.0 -vmm Slot: 00:02.0 Class: VGA compatible controller Vendor: Intel Corporation Device: 4th Gen Core Processor Integrated Graphics Controller SVendor: Lenovo SDevice: Device 3801 Rev: 06 [12:39:58] pietrushnic:~ $ lspci -s 00:02.0 -vmm -n Slot: 00:02.0 Class: 0300 Vendor: 8086 Device: 0416 SVendor: 17aa SDevice: 3801 Rev: 06 If you need more information I would be glad to help with debugging and testing. Regards, Piotr Król
Please attach dmesg with drm.debug=0xe from early boot to the problem, without the invert_brightness module parameter. Can you adjust brightness? What do you have in /sys/class/backlight?
Created attachment 106153 [details] dmesg with drm.debug=0xe
Created attachment 106154 [details] /sys/class/backlight
Yes I can adjust brightness using function keys. /sys/class/backlight └── intel_backlight -> ../../devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight 1 directory, 0 files
I have new observation, beacuse I'm using dual monitor setup (laptop + samsung over hdmi) I didn't realize that disconnecting HDMI and booting with i915.invert_brightness=1 cause laptop screen is black and I cannot increase brightness or switch to tty console. After removing i915 parameter y510p boots with normal scree brightness. So it is definitely related with dual monitor configuration.
Let me get this straight: without the external monitor everything works fine, and you don't need to use i915.invert_brightness=1? (And in fact the parameter breaks things in this setup.)
Exactly. The problem is that configuration with dual monitor start with dimmed screen without i915.invert_brightness=1, so option is needed, but when I add it permanently and want to take my laptop away (disconnect second monitor) I cannot see anything - screen is blank (this is not dimmed screen - this is other problem).
Let's focus on *not* adding i915.invert_brightness=1. Is there a difference between booting with the external monitor connected vs. disconnected and hotplugged later?
No there is no difference in both cases laptop screen brightness going to 0. I checked on 3.17.0-rc3, rc5 and rc6.
Long time no updates. Please try drm-intel-nightly branch of http://cgit.freedesktop.org/drm-intel
Timing out, hopefully it's not an issue anymore or the machine has been destroyed in a fire.
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