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Bug 1571876 - [Regression] Unable to adjust backlight with kernel 4.15 on Dell L421X (XPS 14)
Summary: [Regression] Unable to adjust backlight with kernel 4.15 on Dell L421X (XPS 14)
Keywords:
Status: CLOSED DUPLICATE of bug 1571036
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 27
Hardware: x86_64
OS: Linux
unspecified
high
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2018-04-25 15:03 UTC by Alessandro Guido
Modified: 2018-04-25 16:18 UTC (History)
17 users (show)

Fixed In Version:
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Clone Of:
Environment:
Last Closed: 2018-04-25 16:18:10 UTC
Type: Bug
Embargoed:

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Description Alessandro Guido 2018-04-25 15:03:51 UTC 
With kernel version 4.15 it is impossible to adjust the display backlight. Booting the same system with kernel 4.13 gives a working backlight out-of-the-box.

By looking inside "/sys/class/backlight" I can see that "acpi_video0" backlight module is not registered anymore on 4.15. The "intel_backlight" is present both in 4.13 and 4.15 but it hasn't ever worked.

I tried setting acpi_backlight to any of "video", "vendor", "native", "none" with no effects.
Comment 1 Jeremy Cline 2018-04-25 16:18:10 UTC 
Hi Alessandro,

Can you test the 4.16.4 kernel update[0]? It should fix this.

[0] https://bodhi.fedoraproject.org/updates/FEDORA-2018-e71875c4aa

*** This bug has been marked as a duplicate of bug 1571036 ***
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