lock screen does not turn off backlight while active (nouveau/ThinkPad P52)

[noseshimself]

Qubes OS version
R4.0, kernel-latest

Affected component(s) or functionality
X11

Brief summary
Activate the lock screen. The backlight stays on.

To Reproduce
See summary.

Expected behavior
While the screen is locked the backlight should be turned off.

Actual behavior
It glows eerily in the dark.

Additional context
Backlight control on Lenovo P52 with nouveau started working with kernel 5.0.7 BUT currently requires a modified xen.cfg enty:

kernel=vmlinuz-5.0.9-1.pvops.qubes.x86_64 [...] acpi_backlight=vendor acpi_osi="Linux" thinkpad-acpi.brightness_enable=1 nouveau.modeset=1 [...]

It seems that the currently used lockscreen is not up to the task and also cannot be configured to use alternative ways of controlling screen brightness.

Solutions you've tried
Installing Arch Linux helps tremendously.

Please consider replacing the component.

[red-avalanche]

This seems like an old issue, but I am seeing it today so I'm not sure if it's been fixed.

Qubes OS version
xen_version: 4.14.4
Linux 5.10.104-3.fc32.qubes.x86_64

Affected component(s) or functionality
X11

Brief summary
Same as initial issue

To Reproduce
See summary.

Expected behavior
While the screen is locked the backlight should be turned off.

Actual behavior
It glows eerily in the dark.

Additional context
Desktop with Nvidia 1080Ti, Ryzen 3700 CPU, and Samsung Odyssey monitor over DisplayPort.

Solutions you've tried
I tried changing the settings in xen.cfg as in the original issue but it had no effect for me.

[DemiMarie]

This is an XScreenSaver bug. Not sure if it will be fixed, but it will go away if the GUI ever switches to Wayland.

[red-avalanche]

I believe Qubes needs to provide a newer version of XScreenSaver (or dom0) to address this bug. Went to submit a bug report and found this on the bug reporting site:

If you think you have found a bug, please let me know! The Bugs page explains how to submit a useful bug report. But the very first thing you should do is try the latest version to see if the bug is already fixed. Particularly if you are not yet using version 6.

I tried upgrading by manually downloading the .rpm but encountered dependency hell with basic things like outdated glibc. From the xscreensaver package name (xscreensaver-base-1:5.45-5.fc32.x86_64) it looks like it's gathered from Fedora 32? Version 5.45 of XScreenSaver was released 8 Dec 2020 so it's quite old.

Reading the change logs version 6.02 may help.

X11: “Disable Screen Saver” was behaving like “Blank Screen Only”.

[DemiMarie]

@marmarek any chance we can do that?

[unman]

[quote] @marmarek any chance we can do that? [/quote] FYI I had put in PR to create QScreensaver based on 6, but it isn't included in 4.1