You are not logged in.

#1 2025-10-10 13:24:12

RaphaelB
Member
Registered: 2025-10-10
Posts: 10

Slow kernel boot due to amdgpu modsetting

Hello everyone. I ran dmesg and it turns out my kernel is spending 16 seconds doing "amdgpu kernel modsetting" on startup:

    [    3.228833] [drm] radeon kernel modesetting enabled.
    [    3.228973] radeon 0000:00:01.0: CIK support disabled by module param
    [   19.337278] [drm] amdgpu kernel modesetting enabled.

For more context, I use a UKI built using this command:

    ukify build 
      --linux=/boot/vmlinuz-linux 
      --microcode=/boot/amd-ucode.img 
      --initrd=/boot/initramfs-linux.img 
      --cmdline="
          amdgpu.cik_support=1 radeon.cik_support=0 
          root=UUID=70feb3c8-ba66-42fd-b41d-9b6dec041451 
          rw" 
      --output=/boot/EFI/BOOT/BOOTX64.EFI

I managed to get amdgpu enabled earlier in the process using MODULES= in initramfs, but it still takes just as long. I've followed every relevant step, as far as I can tell, on the AMDGPU page.

Would appreciate any informed advice or comments.

Last edited by RaphaelB (2025-10-13 08:54:41)

Offline

#2 2025-10-13 10:39:45

Lone_Wolf
Administrator
From: Netherlands, Europe
Registered: 2005-10-04
Posts: 14,315

Re: Slow kernel boot due to amdgpu modsetting

https://wiki.archlinux.org/title/General_guidelines wrote:

If people are reading your thread without answering or offering help, you may try supplying more details, or ask to be pointed in the right direction

as root  / with root rights run

# journalctl -b | curl -F 'file=@-' 0x0.st

This will upload the journal of your current boot to a public hosting site and ouput a link. Post that link.

The output of systemd-analyze blame would also be helpful.


Disliking systemd intensely, but not satisfied with alternatives so focusing on taming systemd.

clean chroot building not flexible enough ?
Try clean chroot manager by graysky

Offline

#3 2025-10-14 13:36:57

RaphaelB
Member
Registered: 2025-10-10
Posts: 10

Re: Slow kernel boot due to amdgpu modsetting

Thank you for replying.

journalctl: www.0x0.st/KSuv.txt
systemd-analyze: www.0x0.st/KSux.txt
dmesg: www.0x0.st/KSu3.txt

I didn't previously post my systemd-analyze output since it only lists durations in user space and this issue is in kernel space. But I've put it here along with the full dmesg if it can help at all.

Offline

#4 2025-10-14 13:45:52

seth
Member
From: Don't DM me only for attention
Registered: 2012-09-03
Posts: 69,145

Re: Slow kernel boot due to amdgpu modsetting

Sep 24 10:18:02 briand kernel: Linux version 6.17.1-arch1-1 (linux@archlinux) (gcc (GCC) 15.2.1 20250813, GNU ld (GNU Binutils) 2.45.0) #1 SMP PREEMPT_DYNAMIC Mon, 06 Oct 2025 18:48:29 +0000
Sep 24 10:18:02 briand kernel: Command line: amdgpu.cik_support=1 radeon.cik_support=0 root=UUID=70feb3c8-ba66-42fd-b41d-9b6dec041451 rw
Sep 24 10:18:02 briand kernel: Kernel command line: amdgpu.cik_support=1 radeon.cik_support=0 root=UUID=70feb3c8-ba66-42fd-b41d-9b6dec041451 rw
Sep 24 10:18:02 briand kernel: [drm] amdgpu kernel modesetting enabled.
Sep 24 10:18:02 briand kernel: amdgpu: Virtual CRAT table created for CPU
Sep 24 10:18:02 briand kernel: amdgpu: Topology: Add CPU node
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: initializing kernel modesetting (KABINI 0x1002:0x983D 0x144D:0xC730 0x00).
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: register mmio base: 0xFEB00000
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: register mmio size: 262144
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: detected ip block number 0 <cik_common>
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: detected ip block number 1 <gmc_v7_0>
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: detected ip block number 2 <cik_ih>
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: detected ip block number 3 <gfx_v7_0>
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: detected ip block number 4 <cik_sdma>
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: detected ip block number 5 <kv_dpm>
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: detected ip block number 6 <dce_v8_0>
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: detected ip block number 7 <uvd_v4_2>
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: detected ip block number 8 <vce_v2_0>
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: Fetched VBIOS from VFCT
Sep 24 10:18:02 briand kernel: amdgpu: ATOM BIOS: BR44600
Sep 24 10:18:02 briand kernel: kfd kfd: amdgpu: KABINI  not supported in kfd
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: vgaarb: deactivate vga console
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: Trusted Memory Zone (TMZ) feature not supported
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: vm size is 64 GB, 2 levels, block size is 10-bit, fragment size is 9-bit
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: VRAM: 512M 0x0000000F00000000 - 0x0000000F1FFFFFFF (512M used)
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: GART: 1024M 0x0000000000000000 - 0x000000003FFFFFFF
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: amdgpu: 512M of VRAM memory ready
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: amdgpu: 1674M of GTT memory ready.
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: [drm] Internal thermal controller without fan control
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: [drm] dpm initialized
Sep 24 10:18:02 briand kernel: [drm] amdgpu atom DIG backlight initialized
Sep 24 10:18:02 briand kernel: [drm] AMDGPU Display Connectors
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: SE 1, SH per SE 1, CU per SH 2, active_cu_number 2
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: amdgpu: Runtime PM not available
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: [drm] Registered 2 planes with drm panic
Sep 24 10:18:02 briand kernel: [drm] Initialized amdgpu 3.64.0 for 0000:00:01.0 on minor 1
Sep 24 10:18:02 briand kernel: fbcon: amdgpudrmfb (fb0) is primary device
Sep 24 10:18:02 briand kernel: amdgpu 0000:00:01.0: [drm] fb0: amdgpudrmfb frame buffer device
Sep 24 10:18:02 briand kernel: [drm] radeon kernel modesetting enabled.

the journal doesn't reflect such delay at all.

[    1.553342] usb 4-2: new full-speed USB device number 2 using ohci-pci
[    1.706408] usb 4-2: New USB device found, idVendor=0cf3, idProduct=3004, bcdDevice= 0.01
[    1.706430] usb 4-2: New USB device strings: Mfr=0, Product=0, SerialNumber=0
[    1.784487] ACPI: video: Video Device [VGA1] (multi-head: yes  rom: no  post: no)
[    1.785315] input: Video Bus as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/LNXVIDEO:01/input/input5
[    1.891305] tsc: Refined TSC clocksource calibration: 998.127 MHz
[    1.891330] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x1cc65b93289, max_idle_ns: 881590487074 ns
[    1.891381] clocksource: Switched to clocksource tsc
[    2.658716] usb 1-3: new high-speed USB device number 3 using ehci-pci
[    2.868968] usb 1-3: New USB device found, idVendor=2232, idProduct=1054, bcdDevice= 0.15
[    2.868983] usb 1-3: New USB device strings: Mfr=3, Product=1, SerialNumber=2
[    2.868989] usb 1-3: Product: WebCam SC-10HDD13335N
[    2.868994] usb 1-3: Manufacturer: Generic
[    2.868999] usb 1-3: SerialNumber: 200901010001
[   17.824727] [drm] amdgpu kernel modesetting enabled.

amdgpu is in the initramfs and loads ahead of radeon - can you disable the webcam?

Online

#5 2025-10-14 14:06:16

RaphaelB
Member
Registered: 2025-10-10
Posts: 10

Re: Slow kernel boot due to amdgpu modsetting

I created a file named "/etc/modprobe.d/disable_webcam.conf" containing "blacklist uvcvideo" and on a reboot the webcam can't be accessed, so I believe I disabled it correctly. The amdgpu delay persists and is unaffected.

Offline

#6 2025-10-14 14:07:27

seth
Member
From: Don't DM me only for attention
Registered: 2012-09-03
Posts: 69,145

Re: Slow kernel boot due to amdgpu modsetting

No, in the UEFI settings (if it's a built-in device) - the problem would be the usb access, not then the uvcvideo module.

Online

#7 2025-10-14 14:31:10

RaphaelB
Member
Registered: 2025-10-10
Posts: 10

Re: Slow kernel boot due to amdgpu modsetting

I'm afraid I don't see any options to manage USB devices in my UEFI BIOS:

https://i.postimg.cc/T1yth9D5/20251014-151856.jpg

I think I've misunderstood something very basic and obvious so apologies if that's the case.

Edit: I am, however, a little concerned that my system time has reset when my laptop ran out of battery. It probably means I need a new CMOS battery and will be why secure boot turned itself back on. But that's a separate issue.

Last edited by RaphaelB (2025-10-14 14:34:05)

Offline

#8 2025-10-14 14:33:03

seth
Member
From: Don't DM me only for attention
Registered: 2012-09-03
Posts: 69,145

Re: Slow kernel boot due to amdgpu modsetting

Have you checked the other pages (security and advanced)?

Online

#9 2025-10-14 14:40:39

RaphaelB
Member
Registered: 2025-10-10
Posts: 10

Re: Slow kernel boot due to amdgpu modsetting

I have, yes.

Offline

#10 2025-10-14 14:50:10

seth
Member
From: Don't DM me only for attention
Registered: 2012-09-03
Posts: 69,145

Re: Slow kernel boot due to amdgpu modsetting

and… roll

https://downloadcenter.samsung.com/cont … al_ENG.pdf
But seems there's no such setting - does some live distro boot uninhibited resp. can you boot w/o delay when using the radeon module?

Online

#11 2025-10-14 15:27:58

RaphaelB
Member
Registered: 2025-10-10
Posts: 10

Re: Slow kernel boot due to amdgpu modsetting

Sorry, and there was no option to disable USB devices there as well.

If I understand you correctly, I was previously using the radeon driver until I switched it to amdgpu, in an attempt to fix this issue. The kernel paused for 20s starting the amdgpu modesetting rather than 16s before the change.

I just tried to boot to the Arch live USB but it couldn't find root: https://i.postimg.cc/0KD2QBg2/20251014-161714.jpg

However, the live USB does have a more featured BIOS and may let me disable some if that would help.

Before I go further, could you explain for my understanding please what you suspect might be causing the issue, and why you are proposing disabling the webcam and booting into a live environment? I very much appreciate the help but I would like to understand better the boot modesetting process and the attempts at diagnosis.

Offline

#12 2025-10-14 19:00:19

seth
Member
From: Don't DM me only for attention
Registered: 2012-09-03
Posts: 69,145

Re: Slow kernel boot due to amdgpu modsetting

I was previously using the radeon driver until I switched it to amdgpu, in an attempt to fix this issue.

You'd run on radeon by default and if you experienced the same delay there it's pretty safe to say that it's not depending on the driver whatsoever.
What happens if you try to boot w/ "nomodeset"?

However, the live USB does have a more featured BIOS and may let me disable some if that would help.

The BIOS is part of the hardware and does not depend on whatever you're booting.
The more important parts of the boot messages are cropped out.

what you suspect might be causing the issue, and why you are proposing disabling the webcam and booting into a live environment?

Live environment just to get away from the current software stack, you can also try https://grml.org/
The webcam is the last thing that shows up before there's apparently a massive delay - if you could disable it that would be a reasonable and easy test to see whether it's holding up anything (because there're no errors - the boot just stalls fro 15s)

Do you encounter the same delay on soft reboots, "systemctl reboot"?

Online

#13 2025-10-14 20:18:40

RaphaelB
Member
Registered: 2025-10-10
Posts: 10

Re: Slow kernel boot due to amdgpu modsetting

You'd run on radeon by default and if you experienced the same delay there it's pretty safe to say that it's not depending on the driver whatsoever.

This was my conclusion too.

What happens if you try to boot w/ "nomodeset"?

I added "nomodeset" to my kernel parameters when running ukify again:

    ukify build 
      --linux=/boot/vmlinuz-linux 
      --microcode=/boot/amd-ucode.img 
      --initrd=/boot/initramfs-linux.img 
      --cmdline="amdgpu.cik_support=1 radeon.cik_support=0 root=UUID=70feb3c8-ba66-42fd-b41d-9b6dec041451 rw nomodeset" 
      --output=/boot/EFI/BOOT/BOOTX64.EFI

I'm not sure if that's the right way of running with nomodeset on my system or if that's what you meant. As I don't have a grub I can't edit the grub entry to add it there. In any case it made no difference.

Do you encounter the same delay on soft reboots, "systemctl reboot"?

Yes, no difference

Offline

#14 2025-10-14 20:25:55

RaphaelB
Member
Registered: 2025-10-10
Posts: 10

Re: Slow kernel boot due to amdgpu modsetting

I booted from the Arch live USB and found that the issue is the same there as well, which I wasn't expecting at all. So maybe the issue is just insurmountable on this machine.

Offline

#15 2025-10-15 07:12:39

seth
Member
From: Don't DM me only for attention
Registered: 2012-09-03
Posts: 69,145

Re: Slow kernel boot due to amdgpu modsetting

Try grml to also run a completely different kernel.
Does it make a difference whether the system runs on battery or AC?

Online

#16 2025-10-15 13:52:15

RaphaelB
Member
Registered: 2025-10-10
Posts: 10

Re: Slow kernel boot due to amdgpu modsetting

Battery or AC certainly doesn't make a difference.

I'll work on testing grml and also finding a way to disable the webcam to implement your other ideas. Thank you for your suggestions.

Last edited by RaphaelB (2025-10-15 13:52:30)

Offline

Board footer

Powered by FluxBB