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Dear all,
Everything was going pretty well on my laptop (HP Envy 15) with nvidia -intel hybrid graphics, with bumblebee installed. A recent update broke the minimum level to which I can change the brightness. Previous it used to go all the way down to zero. But now, even explicitly setting it has no effect on the brightness.
echo 10 > /sys/class/backlight/intel_backlight/brightnessPreviously xbacklight used to work at any level. But even that failed after the upgrade. Though xbacklight can change the brightness once above the "new" minimum level
. However, I can force turn off the display with xset. But thats not what I want. I want to reduce the brigtness even further. How do I do it ?
dmesg | grep i915[ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-linux root=UUID=cd33e22a-52d2-4acb-8cd5-4e5e759f743c ro quiet resume=/dev/mapper/aura--vg-swap_1 pcie_aspm=force i915.enable_rc6=7 i915.enable_fbc=1 i915.semaphores=1 i915.lvds_downclock=1
[ 0.000000] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-linux root=UUID=cd33e22a-52d2-4acb-8cd5-4e5e759f743c ro quiet resume=/dev/mapper/aura--vg-swap_1 pcie_aspm=force i915.enable_rc6=7 i915.enable_fbc=1 i915.semaphores=1 i915.lvds_downclock=1
[ 9.557522] i915 0000:00:02.0: irq 31 for MSI/MSI-X
[ 9.764296] [drm] GMBUS [i915 gmbus vga] timed out, falling back to bit banging on pin 2
[ 10.806509] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[ 10.806511] i915 0000:00:02.0: registered panic notifier
[ 10.906058] [drm] Initialized i915 1.6.0 20140725 for 0000:00:02.0 on minor 0dmesg | grep drm
[ 9.327406] [drm] Initialized drm 1.1.0 20060810
[ 9.518519] [drm] Memory usable by graphics device = 2048M
[ 9.518521] [drm] Replacing VGA console driver
[ 9.519915] [drm] ACPI BIOS requests an excessive sleep of 40000 ms, using 1500 ms instead
[ 9.557530] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[ 9.557531] [drm] Driver supports precise vblank timestamp query.
[ 9.586569] [drm] VBT doesn't support DRRS
[ 9.764296] [drm] GMBUS [i915 gmbus vga] timed out, falling back to bit banging on pin 2
[ 9.778365] fbcon: inteldrmfb (fb0) is primary device
[ 10.806509] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[ 10.906058] [drm] Initialized i915 1.6.0 20140725 for 0000:00:02.0 on minor 0Last edited by aurabindo (2014-11-02 18:40:15)
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I have the same problem (with an other computer model). I think it's a consequence of the commit “drm/i915: respect the VBT minimum backlight brightness” which went into the kernel version 3.17. Hopefully it will be solved by this patch; or the “VBT” minimum backlight brightness is uncomfortably high for some computers…
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I have the same problem (with an other computer model). I think it's a consequence of the commit “drm/i915: respect the VBT minimum backlight brightness” which went into the kernel version 3.17. Hopefully it will be solved by this patch; or the “VBT” minimum backlight brightness is uncomfortably high for some computers…
Thanks for the info!
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I have the same problem (with an other computer model). I think it's a consequence of the commit “drm/i915: respect the VBT minimum backlight brightness” which went into the kernel version 3.17. Hopefully it will be solved by this patch; or the “VBT” minimum backlight brightness is uncomfortably high for some computers…
Didnt this patch make it in to the mainline yet? I think there was a kernel upgrade in arch. I was expecting this fix to be in it. Is there anything we should do ? Like may be submitting a new bug report? Or some way to tell those people that my eyes really hurts?
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Seems like folks at Intel OTC are still figuring out the real cause of problems some users reported, which actually led to the such a restriction. Anyways my computer seems to work fine without such a minimum level. I've filed a bug report. Here is the discussion : http://www.gossamer-threads.com/lists/l … el/2060904. You can get the patch to add an override from the bug report page. They dont seem to be much interested in adding another module parameter. So it still stays open.
I have also made a small write up about it http://aurabindo.in/linux/2014/12/17/my … rightness/
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