Bug 208347

Summary:	Brightness keys stop working after boot into Windows on HP EliteBook x360 1030 G4
Product:	Platform Specific/Hardware	Reporter:	David Rosenstrauch (darose)
Component:	x86-64	Assignee:	platform_x86_64 (platform_x86_64)
Status:	NEW ---
Severity:	normal	CC:	smirnov.sergey, sulaiman
Priority:	P1
Hardware:	x86-64
OS:	Linux
Kernel Version:	5.7.6	Subsystem:
Regression:	No	Bisected commit-id:

Description David Rosenstrauch 2020-06-27 20:01:03 UTC

As described in the comments in:  https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1822581

On my HP EliteBook x360 1030 G4, the brightness up/down keys (F3 and F4) work fine in Linux ... until I boot into Windows.  The brightness keys work fine in Windows as well, but when I then boot back into Linux after that, those keys no longer work.

They remain disabled until I re-install the system BIOS.  (Using the "Update System and Supported Device Firmware" selection from the system utils/boot menu.)  After that the brightness keys work fine again.

It seems like Windows is somehow changing some value in the system BIOS which disables these keys, which Linux isn't restoring.  (I don't know enough about the kernel to know what the issue could be, or to suggest any possible solution.)

Comment 1 Sulicz 2020-07-07 06:09:08 UTC

The same situation on HP ProBook 450 G6.

Comment 2 Sergey 2020-10-04 08:05:31 UTC

Seems to be hardware issue. Flashing latest BIOS haven’t resolved the issue in my case, but power reset have: https://support.hp.com/us-en/document/c01684768