[SOLVED] Dell G15 5515 Ryzen no backlight control on integrated video

hoome · 2023-01-28 14:05:01

Recently I'm having some problems with my integrated graphics on my Dell G15 with a Ryzen 5800H with Vega 8 and a RTX 3060 dedicated graphics.

When the switchable graphics are enable and I'm running the integrated graphics I cannot control the backlight.

I've followed some suggestions and the wiki (at https://wiki.archlinux.org/title/Backlight) and added acpi_backlight parameters to the kernel (i'm running grub).

Changing the value on /sys/class/backlight/amdgpu_bl0/brightness does nothing, as using the hotkeys or changing through KDE interface.

acpi_backlight=video replaces /sys/class/backlight/amdgpu_bl0 with /sys/class/backlight/acpi_video0 but changing the brightness value there does nothing.

acpi_backlight=vendor and acpi_backlight=native removes /sys/class/backlight/amdgpu_bl0 and theres no backlight control.

I've also found amdgpu.backlight, but setting both amdgpu.backlight=0 or amdgpu.backlight=1 does nothing.

I've also exchange the kernel from zen to lts and it does nothing aswell.

dmesg | grep amdgpu

[    1.254335] [drm] amdgpu kernel modesetting enabled.
[    1.256368] amdgpu: Virtual CRAT table created for CPU
[    1.256379] amdgpu: Topology: Add CPU node
[    1.256469] amdgpu 0000:06:00.0: enabling device (0006 -> 0007)
[    1.256563] amdgpu 0000:06:00.0: amdgpu: Trusted Memory Zone (TMZ) feature enabled
[    1.261371] amdgpu 0000:06:00.0: amdgpu: Fetched VBIOS from VFCT
[    1.261372] amdgpu: ATOM BIOS: 113-CEZANNE-018
[    1.262694] amdgpu 0000:06:00.0: vgaarb: deactivate vga console
[    1.262721] amdgpu 0000:06:00.0: amdgpu: VRAM: 512M 0x000000F400000000 - 0x000000F41FFFFFFF (512M used)
[    1.262723] amdgpu 0000:06:00.0: amdgpu: GART: 1024M 0x0000000000000000 - 0x000000003FFFFFFF
[    1.262724] amdgpu 0000:06:00.0: amdgpu: AGP: 267419648M 0x000000F800000000 - 0x0000FFFFFFFFFFFF
[    1.262753] [drm] amdgpu: 512M of VRAM memory ready
[    1.262754] [drm] amdgpu: 3072M of GTT memory ready.
[    1.266901] amdgpu 0000:06:00.0: amdgpu: PSP runtime database doesn't exist
[    1.292913] amdgpu 0000:06:00.0: amdgpu: Will use PSP to load VCN firmware
[    2.109814] amdgpu 0000:06:00.0: amdgpu: RAS: optional ras ta ucode is not available
[    2.119176] amdgpu 0000:06:00.0: amdgpu: RAP: optional rap ta ucode is not available
[    2.119182] amdgpu 0000:06:00.0: amdgpu: SECUREDISPLAY: securedisplay ta ucode is not available
[    2.120409] amdgpu 0000:06:00.0: amdgpu: SMU is initialized successfully!
[    2.304254] kfd kfd: amdgpu: Allocated 3969056 bytes on gart
[    2.366145] amdgpu: HMM registered 512MB device memory
[    2.366201] amdgpu: SRAT table not found
[    2.366203] amdgpu: Virtual CRAT table created for GPU
[    2.366309] amdgpu: Topology: Add dGPU node [0x1638:0x1002]
[    2.366320] kfd kfd: amdgpu: added device 1002:1638
[    2.366433] amdgpu 0000:06:00.0: amdgpu: SE 1, SH per SE 1, CU per SH 8, active_cu_number 8
[    2.369560] fbcon: amdgpudrmfb (fb0) is primary device
[    3.243022] amdgpu 0000:06:00.0: [drm] fb0: amdgpudrmfb frame buffer device
[    3.275009] amdgpu 0000:06:00.0: amdgpu: ring gfx uses VM inv eng 0 on hub 0
[    3.275017] amdgpu 0000:06:00.0: amdgpu: ring comp_1.0.0 uses VM inv eng 1 on hub 0
[    3.275021] amdgpu 0000:06:00.0: amdgpu: ring comp_1.1.0 uses VM inv eng 4 on hub 0
[    3.275023] amdgpu 0000:06:00.0: amdgpu: ring comp_1.2.0 uses VM inv eng 5 on hub 0
[    3.275024] amdgpu 0000:06:00.0: amdgpu: ring comp_1.3.0 uses VM inv eng 6 on hub 0
[    3.275026] amdgpu 0000:06:00.0: amdgpu: ring comp_1.0.1 uses VM inv eng 7 on hub 0
[    3.275030] amdgpu 0000:06:00.0: amdgpu: ring comp_1.1.1 uses VM inv eng 8 on hub 0
[    3.275032] amdgpu 0000:06:00.0: amdgpu: ring comp_1.2.1 uses VM inv eng 9 on hub 0
[    3.275033] amdgpu 0000:06:00.0: amdgpu: ring comp_1.3.1 uses VM inv eng 10 on hub 0
[    3.275037] amdgpu 0000:06:00.0: amdgpu: ring kiq_2.1.0 uses VM inv eng 11 on hub 0
[    3.275040] amdgpu 0000:06:00.0: amdgpu: ring sdma0 uses VM inv eng 0 on hub 1
[    3.275044] amdgpu 0000:06:00.0: amdgpu: ring vcn_dec uses VM inv eng 1 on hub 1
[    3.275047] amdgpu 0000:06:00.0: amdgpu: ring vcn_enc0 uses VM inv eng 4 on hub 1
[    3.275048] amdgpu 0000:06:00.0: amdgpu: ring vcn_enc1 uses VM inv eng 5 on hub 1
[    3.275052] amdgpu 0000:06:00.0: amdgpu: ring jpeg_dec uses VM inv eng 6 on hub 1
[    3.277426] [drm] Initialized amdgpu 3.42.0 20150101 for 0000:06:00.0 on minor 0

journalctl -b 0 | grep amdgpu

Jan 28 10:53:01 lara kernel: Command line: BOOT_IMAGE=/vmlinuz-linux-lts root=UUID=a2dd31fd-dd99-4dd9-9310-542d31c37296 rw acpi_backlight=video loglevel=3 quiet acpi_backlight=video
Jan 28 10:53:01 lara kernel: Kernel command line: BOOT_IMAGE=/vmlinuz-linux-lts root=UUID=a2dd31fd-dd99-4dd9-9310-542d31c37296 rw acpi_backlight=video loglevel=3 quiet acpi_backlight=video
Jan 28 10:53:02 lara systemd[1]: Created slice Slice /system/systemd-backlight.
Jan 28 10:53:02 lara systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0...
Jan 28 10:53:03 lara systemd[1]: Finished Load/Save Screen Backlight Brightness of backlight:amdgpu_bl0.
Jan 28 10:53:03 lara audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=systemd-backlight@backlight:amdgpu_bl0 comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Jan 28 10:53:04 lara systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:acpi_video0...
Jan 28 10:53:04 lara systemd[1]: Finished Load/Save Screen Backlight Brightness of backlight:acpi_video0.
Jan 28 10:53:04 lara audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 msg='unit=systemd-backlight@backlight:acpi_video0 comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Jan 28 10:53:45 lara dbus-daemon[644]: [system] Activating service name='org.kde.powerdevil.backlighthelper' requested by ':1.53' (uid=1000 pid=1529 comm="/usr/lib/org_kde_powerdevil") (using servicehelper)
Jan 28 10:53:45 lara dbus-daemon[644]: [system] Successfully activated service 'org.kde.powerdevil.backlighthelper'

I cannot find any indication that there is something wrong with the driver itself the backlight just doesn't work. It worked about 2 days ago and I dont know what made it stop working. When I do boot with the dedicated graphics alone (this laptop has a mux switch that can be set on BIOS) i got backlight control again but running a RTX 3060 on a laptop all the time has basically the same effect as not having the backlight control, the laptop runs very hot and the battery drains very fast. If anyone can help me with that issue.

Last edited by hoome (2023-04-25 19:14:26)

hoome · 2023-01-28 16:28:40

Well... After futher testing,

I've installed Windows 11 on a separated SSD for 2 reasons, to check if it wasn't a hardware issue and to check if the laptop wasn't on a weird state (happens to me before on switchable graphics laptop). The good news is that the backlight worked on Windows until... I've installed the latest nvidia driver and the backlight stopped again.

I've found this thread for Windows users on Dell forums for the same problem: https://www.dell.com/community/Inspiron … 621/page/2

And the solution was to downgrade the driver to 522.25 and once i've downgraded on Windows the backlight started working without even needing a reboot.

Okay, so do the same thing on Linux and... Well... Downgrade way back to 495.46 with linux-lts and no luck, the backlight still doesn't work... Also tried "nvidia.NVreg_RegistryDwords=EnableBrightnessControl=1" without success.

bruceg · 2023-01-30 01:26:01

I have the same laptop, and the same hardware, and was just about to post a bug report about this.

The problem I'm seeing is that the 6.1 kernel series appears to have regressed the backlight control. Here's what I've found:

On this hardware, when switchable graphics are enabled, the display panel is connected to the iGPU on the CPU and the external displays are connected to the Nvidia dGPU. The unusual part (to me, at least) is that the backlight control is connected to the Nvidia dGPU. This requires a kernel module that appeared in either the 5.15 or 6.0 kernel series, don't recall which now, called nvidia_wmi_ec_backlight. Despite its name, it's actually part of the standard Linux kernel and works even when the proprietary nvidia driver is not present. I have tested with the nvidia driver completely uninstalled.

On the 6.0 kernel series, two backlights appear in /sys/class/backlight: amdgpu_bl0 and nvidia_wmi_ec_backlight. The former appears to be a dummy device present on the iGPU but not actually attached to anything. It is the latter that controls the display panel backlight.

On the 6.1 kernel series, I have been unable to get the nvidia backlight control to appear. The module loads, prints nothing, but the control doesn't work.

With acpi_backlight=native, only amdgpu_bl0 appears
With acpi_backlight=video, only acpi_video0 appears
With acpi_backlight=vendor, no backlight controls are present at all.

I'm not sure where to go with this. For now, I have downgraded to the 6.0 kernel so the backlight works, but that is EOL and so I'm kinda stuck.

bruceg · 2023-02-14 05:16:25

Upstream bug report: https://bugzilla.kernel.org/show_bug.cgi?id=216138

bruceg · 2023-02-15 04:39:48

I just discovered that we can use the following kernel command line option to enable this backlight:

acpi_backlight=nvidia_wmi_ec

With this option, the backlight functions again for me, both with and without the proprietary nvidia modules loaded.

Solved?

hoome · 2023-04-25 19:14:11

bruceg wrote:

I just discovered that we can use the following kernel command line option to enable this backlight:
acpi_backlight=nvidia_wmi_ec
With this option, the backlight functions again for me, both with and without the proprietary nvidia modules loaded.
Solved?

I ended up stashing this laptop away for a while and got it today.

And i can confirm. Setting `acpi_backlight=nvidia_wmi_ec` as kernel parameter made the backlight work again.

Arch Linux

#1 2023-01-28 14:05:01

[SOLVED] Dell G15 5515 Ryzen no backlight control on integrated video

#2 2023-01-28 16:28:40

Re: [SOLVED] Dell G15 5515 Ryzen no backlight control on integrated video

#3 2023-01-30 01:26:01

Re: [SOLVED] Dell G15 5515 Ryzen no backlight control on integrated video

#4 2023-02-14 05:16:25

Re: [SOLVED] Dell G15 5515 Ryzen no backlight control on integrated video

#5 2023-02-15 04:39:48

Re: [SOLVED] Dell G15 5515 Ryzen no backlight control on integrated video

#6 2023-04-25 19:14:11

Re: [SOLVED] Dell G15 5515 Ryzen no backlight control on integrated video

Board footer