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Bug 1571036 - Kernel updates breaks screen brightness keys
Summary: Kernel updates breaks screen brightness keys
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 27
Hardware: x86_64
OS: Linux
unspecified
medium
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
: 1570414 1571876 (view as bug list)
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2018-04-24 01:55 UTC by laolux
Modified: 2018-05-11 17:45 UTC (History)
19 users (show)

Fixed In Version: kernel-4.16.4-300.fc28 kernel-4.16.4-200.fc27 kernel-4.16.7-100.fc26
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2018-04-27 23:07:17 UTC
Type: Bug
Embargoed:

Attachments (Terms of Use)

Description laolux 2018-04-24 01:55:40 UTC 
Description of problem:
With newer kernels, namely 4.15.17-300.fc27.x86_64 and 4.16.3-200.fc27.x86_64 the keys to change the brightness of my laptop screen do not work any more. Booting older kernels like 4.15.16-300.fc27.x86_64 or before, the brightness keys do work. So it must be a regression with a recent kernel update.

Version-Release number of selected component (if applicable):
4.15.17-300.fc27.x86_64
4.16.3-200.fc27.x86_64

How reproducible:
Reproducible every time. When I select a new kernel in grub, then the brightness keys never work. When I select an old kernel in grub, then the brightness keys always work.

Steps to Reproduce:
1. Boot computer with new kernel
2. Login
3. Try the keyboard keys to increase/decrease screen brightness

Actual results:
Nothing happens, screen brightness stays fixed.

Expected results:
Screen gets brighter/darker.

Additional info:
Laptop is about 5 years old, MSI, Intel Core i7-3630QM. Never had an issue with the screen brightness in old versions of fedora.
This issue severely impacts battery life and the possibility to work in very bright/dark environments.
Comment 1 Jeremy Cline 2018-04-24 18:58:04 UTC 
Hi,

Thanks for the bug report. One commit that jumped out at me between 4.15.16 and 4.15.17 is 965736ee654db8bb009a9736e52cac0278a24a8b. If you boot 4.15.17 with "video.only_lcd=0" added to the kernel command line, does that make any difference?

What's the output of "ls /sys/class/backlight"?
Comment 2 Hans de Goede 2018-04-24 19:05:35 UTC 
Hi,

(In reply to Jeremy Cline from comment #1)
> Hi,
> 
> Thanks for the bug report. One commit that jumped out at me between 4.15.16
> and 4.15.17 is 965736ee654db8bb009a9736e52cac0278a24a8b. If you boot 4.15.17
> with "video.only_lcd=0" added to the kernel command line, does that make any
> difference?

Oh, good call Jeremy in case you've not seen it yet, here is a commit which
should fix the regressions caused by that commit:

https://patchwork.kernel.org/patch/10345845/

Perhaps we should add this to the Fedora kernel while it finds it way upstream?

> What's the output of "ls /sys/class/backlight"?

If "video.only_lcd=0" helps then it likely is empty without that kernel argument. Laolux can you confirm this?

Regards,

Hans
Comment 3 Jeremy Cline 2018-04-24 19:17:04 UTC 
(In reply to Hans de Goede from comment #2)
> Hi,
> 
> (In reply to Jeremy Cline from comment #1)
> > Hi,
> > 
> > Thanks for the bug report. One commit that jumped out at me between 4.15.16
> > and 4.15.17 is 965736ee654db8bb009a9736e52cac0278a24a8b. If you boot 4.15.17
> > with "video.only_lcd=0" added to the kernel command line, does that make any
> > difference?
> 
> Oh, good call Jeremy in case you've not seen it yet, here is a commit which
> should fix the regressions caused by that commit:
> 
> https://patchwork.kernel.org/patch/10345845/
> 
> Perhaps we should add this to the Fedora kernel while it finds it way
> upstream?

Ah, I hadn't seen that, thanks! I'll see about including it with the v4.16.4 update once I sort out the build failures.
Comment 4 Jeremy Cline 2018-04-24 22:02:31 UTC 
*** Bug 1570414 has been marked as a duplicate of this bug. ***
Comment 5 Fedora Update System 2018-04-25 13:26:09 UTC 
kernel-4.16.4-300.fc28 has been submitted as an update to Fedora 28. https://bodhi.fedoraproject.org/updates/FEDORA-2018-5926c0ffc8
Comment 6 Fedora Update System 2018-04-25 13:26:35 UTC 
kernel-4.16.4-200.fc27 has been submitted as an update to Fedora 27. https://bodhi.fedoraproject.org/updates/FEDORA-2018-e71875c4aa
Comment 7 Jeremy Cline 2018-04-25 13:39:43 UTC 
Laolux, Oswaldo,

In addition to seeing if "video.only_lcd=0" helps, can you both also test the 4.16.4 update and let us know if that works? Assuming 965736ee654db is the root cause, it should fix things for you, but there's a non-zero chance additional tweaking will be required depending on your hardware.

Thanks!
Comment 8 laolux 2018-04-25 15:17:17 UTC 
Problem solved.

Using 4.15.17, "ls /sys/class/backlight" outputs nothing.
Adding "video.only_lcd=0" repairs the brightness adjustment with the keyboard keys for both, 4.15.17 and 4.16.3. It also changes the output of "ls /sys/class/backlight" to
acpi_video0 -> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/backlight/acpi_video0
acpi_video0 -> ../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/backlight/acpi_video0

Kernel 4.16.4 completely fixes the problem, as "video.only_lcd=0" is no longer needed.

Thanks a lot!
Comment 9 Jeremy Cline 2018-04-25 16:18:10 UTC 
*** Bug 1571876 has been marked as a duplicate of this bug. ***
Comment 10 Fedora Update System 2018-04-26 04:53:08 UTC 
kernel-4.16.4-300.fc28 has been pushed to the Fedora 28 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2018-5926c0ffc8
Comment 11 Fedora Update System 2018-04-26 13:10:12 UTC 
kernel-4.16.4-100.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2018-884a105c04
Comment 12 Fedora Update System 2018-04-27 07:14:28 UTC 
kernel-4.16.4-100.fc26 has been pushed to the Fedora 26 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2018-884a105c04
Comment 13 Fedora Update System 2018-04-27 07:54:22 UTC 
kernel-4.16.4-200.fc27 has been pushed to the Fedora 27 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2018-e71875c4aa
Comment 14 Fedora Update System 2018-04-27 23:07:17 UTC 
kernel-4.16.4-300.fc28 has been pushed to the Fedora 28 stable repository. If problems still persist, please make note of it in this bug report.
Comment 15 Fedora Update System 2018-04-28 16:15:39 UTC 
kernel-4.16.5-100.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2018-884a105c04
Comment 16 Fedora Update System 2018-04-29 05:15:26 UTC 
kernel-4.16.4-200.fc27 has been pushed to the Fedora 27 stable repository. If problems still persist, please make note of it in this bug report.
Comment 17 Fedora Update System 2018-05-01 14:59:48 UTC 
kernel-4.16.6-100.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2018-884a105c04
Comment 18 Fedora Update System 2018-05-02 09:51:48 UTC 
kernel-4.16.6-100.fc26 has been pushed to the Fedora 26 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2018-884a105c04
Comment 19 Fedora Update System 2018-05-03 12:33:39 UTC 
kernel-4.16.7-100.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2018-884a105c04
Comment 20 Fedora Update System 2018-05-06 05:34:01 UTC 
kernel-4.16.7-100.fc26 has been pushed to the Fedora 26 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2018-884a105c04
Comment 21 Fedora Update System 2018-05-11 17:45:20 UTC 
kernel-4.16.7-100.fc26 has been pushed to the Fedora 26 stable repository. If problems still persist, please make note of it in this bug report.
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