Bug 348882 - KDE cannot set backlight anymore, kernel can
Summary: KDE cannot set backlight anymore, kernel can
Status: RESOLVED WORKSFORME
Alias: None
Product: Powerdevil
Classification: Plasma
Component: general (show other bugs)
Version: unspecified
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: Plasma Development Mailing List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-06-08 13:48 UTC by azrdev
Modified: 2020-12-12 04:34 UTC (History)
2 users (show)

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Description azrdev 2015-06-08 13:48:40 UTC
Since the last KDE update[1] on my archlinux, KDE cannot set the screen backlight anymore. When `echo`ing to /sys/class/backlight/radeon_bl0/brightness it works fine (as before), but if I press the XF86MonBrightness{Down,Up} buttons, or use the battery plasma widget to adjust the brightness, nothing happens except some log messages [2] about backlighthelper being started. Those had been there identically when it still worked.
The brightness control of the battery widget initially shows 0%, previously it showed the actual current level.

uname: Linux host 4.0.4-2-ARCH #1 SMP PREEMPT Fri May 22 03:05:23 UTC 2015 x86_64 GNU/Linux
As in the current archlinux repos, my system has mixed KDE4 and KF5 components running: I can tell the versions if there's anything specific of interest.
My graphics card is the embedded Radeon HD 7340 in my E2-1800 Zacate CPU, see [3]

[1] excerpt from /var/log/pacman.log :
[2015-05-13 09:46] [ALPM] upgraded kdebase-workspace (4.11.18-1 -> 4.11.19-1)
[2015-05-13 09:46] [ALPM] upgraded kdebase-plasma (15.04.0-3 -> 15.04.1-1)

[2] from journal:
Jun 08 15:39:50 host dbus[236]: [system] Activating service name='org.kde.powerdevil.backlighthelper' (using servicehelper)
Jun 08 15:39:50 host org.kde.powerdevil.backlighthelper[16793]: QDBusConnection: system D-Bus connection created before QCoreApplication. Application may misbehave.
Jun 08 15:39:50 host dbus[236]: [system] Successfully activated service 'org.kde.powerdevil.backlighthelper'

[3] sudo lspci -nnk -v -s 00:01.0  # my graphics card
00:01.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Wrestler [Radeon HD 7340] [1002:9808] (prog-if 00 [VGA controller])
        Subsystem: Lenovo Device [17aa:5105]
        Flags: bus master, fast devsel, latency 0, IRQ 32
        Memory at e0000000 (32-bit, prefetchable) [size=256M]
        I/O ports at 3000 [size=256]
        Memory at f0b00000 (32-bit, non-prefetchable) [size=256K]
        Expansion ROM at <unassigned> [disabled]
        Capabilities: [50] Power Management version 3
        Capabilities: [58] Express Root Complex Integrated Endpoint, MSI 00
        Capabilities: [a0] MSI: Enable+ Count=1/1 Maskable- 64bit+
        Capabilities: [100] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?>
        Kernel driver in use: radeon
        Kernel modules: radeon


Reproducible: Always
Comment 1 Kai Uwe Broulik 2015-06-16 18:02:04 UTC
Those packages confuse me. You have workspace 4.11.19 installed as well as plasma 15.04?! There's no plasma 15.04, that's application versioning scheme.
Comment 2 azrdev 2015-06-16 18:48:43 UTC
@Kai: maybe this stems from the KDE4 → KF5 transition of archlinux, which started in december(?) by moving applications each as soon as it was ported - at least that's how I understood it. plasma was not yet migrated at that point, I'm not sure if it is ready now - the arch wiki [1][2] mostly says it's an exclusive decision, i.e. I cannot install plasma4 and 5 simultaneously.

Having said that, my system currently consists of the plasma4 desktop, and some of the applications from KF5 (gwenview, konsole, ...), the others still on KDE4 (systemsettings, dolphin, ...). Both kded4 and kded5 are running.

[1] <https://wiki.archlinux.org/index.php/KDE#Installation>
[2] <https://wiki.archlinux.org/index.php/Plasma#Installation>
Comment 3 Justin Zobel 2020-11-12 21:31:18 UTC
I've just tested this on KDE Neon User Edition and I'm unable to replicate the issue.

Can you please test and confirm if this issue is still occurring or if this bug report can be marked as resolved. I'm setting status to "needsinfo" pending your response, please change back to "reported" or "resolved" when you respond, thanks.
Comment 4 Bug Janitor Service 2020-11-27 04:33:53 UTC
Dear Bug Submitter,

This bug has been in NEEDSINFO status with no change for at least
15 days. Please provide the requested information as soon as
possible and set the bug status as REPORTED. Due to regular bug
tracker maintenance, if the bug is still in NEEDSINFO status with
no change in 30 days the bug will be closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

If you have already provided the requested information, please
mark the bug as REPORTED so that the KDE team knows that the bug is
ready to be confirmed.

Thank you for helping us make KDE software even better for everyone!
Comment 5 Bug Janitor Service 2020-12-12 04:34:05 UTC
This bug has been in NEEDSINFO status with no change for at least
30 days. The bug is now closed as RESOLVED > WORKSFORME
due to lack of needed information.

For more information about our bug triaging procedures please read the
wiki located here:
https://community.kde.org/Guidelines_and_HOWTOs/Bug_triaging

Thank you for helping us make KDE software even better for everyone!