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Oleksa75
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Joined: 18 Oct 2021
Posts: 19
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 Posted: Tue Nov 19, 2024 1:53 pm Post subject: Kernel 6.12 - booting hanged in real PREEMPT_RT mode |
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Hello there!
As we know, the real big one for release 6.12 is the enabling of PREEMPT_RT, implementing real-time computing capabilities.
Kernel from Gentoo repos was compiled OK, but I am unable to boot with it - the process hanging with strange phrases smth like "group root:root is invalid".
Please, can you help me to build an investigation plan and find the root of the reason?
Thanks! |
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CaptainBlood
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Joined: 24 Jan 2010
Posts: 3870
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| Posted: Tue Nov 19, 2024 5:19 pm Post subject: |
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Been manually maintaining a specific branch of gentoo-sources with rt flavor for about a decade with almost no upgrade issue.
Migrating 6.11.1 .config to 6.12.0 currently fails to boot.
Console is frozen.
More work is needed for better understanding.
Thks 4 ur attention, interest & support.
_________________
USE="-* ..." in /etc/portage/make.conf here, i.e. a countermeasure to portage implicit braces, belt & diaper paradigm
LT: "I've been doing a passable imitation of the Fontana di Trevi, except my medium is mucus. Sooo much mucus. " |
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Hu
Administrator
Joined: 06 Mar 2007
Posts: 22686
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| Posted: Tue Nov 19, 2024 5:47 pm Post subject: Re: Kernel 6.12 - booting hanged in real PREEMPT_RT mode |
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| Oleksa75 wrote: | As we know, the real big one for release 6.12 is the enabling of PREEMPT_RT, implementing real-time computing capabilities.
Kernel from Gentoo repos was compiled OK, but I am unable to boot with it |
Are you unable to boot any 6.12 kernel, or only unable to boot a PREEMPT_RT 6.12 kernel (but a non-PREEMPT_RT 6.12 kernel works fine)? | Oleksa75 wrote: | | - the process hanging with strange phrases smth like "group root:root is invalid". |
That does not seem like a kernel message. Please give us the exact message, and describe in more detail how you built the non-working kernel. What initramfs (if any) does it use? |
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CaptainBlood
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Joined: 24 Jan 2010
Posts: 3870
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| Posted: Tue Nov 19, 2024 6:10 pm Post subject: |
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All non rt 6.12.0 branches boot fine here, graphic stack included.
Thks 4 ur attention, interest & support.
_________________
USE="-* ..." in /etc/portage/make.conf here, i.e. a countermeasure to portage implicit braces, belt & diaper paradigm
LT: "I've been doing a passable imitation of the Fontana di Trevi, except my medium is mucus. Sooo much mucus. "
Last edited by CaptainBlood on Tue Nov 19, 2024 6:54 pm; edited 1 time in total |
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CaptainBlood
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Joined: 24 Jan 2010
Posts: 3870
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| Posted: Tue Nov 19, 2024 6:44 pm Post subject: |
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I rederived a minimal working 6.12.0 .config to rt.
6.12 rt system boots fine, but display-manager fails to start.
Graphic stack seems failing.
Skylake iGP here.
Thks 4 ur attention, interest & support.
_________________
USE="-* ..." in /etc/portage/make.conf here, i.e. a countermeasure to portage implicit braces, belt & diaper paradigm
LT: "I've been doing a passable imitation of the Fontana di Trevi, except my medium is mucus. Sooo much mucus. " |
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Oleksa75
n00b
Joined: 18 Oct 2021
Posts: 19
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| Posted: Tue Nov 19, 2024 7:19 pm Post subject: |
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| CaptainBlood wrote: | I rederived a minimal working 6.12.0 .config to rt.
6.12 rt system boots fine, but display-manager fails to start.
Graphic stack seems failing.
Skylake iGP here.
Thks 4 ur attention, interest & support. |
Correct! The same for me, and seems I've found root of reason
| Code: | | thinkbox /tmp # lspci -nnkv | grep -i VGA |
00:02.0 VGA compatible controller [0300]: Intel Corporation Raptor Lake-P [UHD Graphics] [8086:a721] (rev 04) (prog-if 00 [VGA controller])
thinkbox /tmp # make menuconfig
Then select
Device Drivers > Graphics support > Direct Rendering Manager (XFree86 4.1.0 and higher DRI support)
<M> Intel Xe Graphics
In section "Force probe xe for selected Intel hardware IDs" I posted "a721"
This force procedure leads to unable boot with real RT:
[1.341040] xe 0000:00:02.0: Your graphics device a721 is not officially supported
by xe driver in this kernel version. To force Xe probe,
use xe.force_probe='a721' and i915.force_probe='!a721'
module parameters or CONFIG_DRM_XE_FORCE_PROBE='a721' and
CONFIG_DRM_I915_FORCE_PROBE='!a721' configuration options. |
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CaptainBlood
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Joined: 24 Jan 2010
Posts: 3870
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| Posted: Tue Nov 19, 2024 8:16 pm Post subject: |
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Here | Code: | Symbol: DRM_I915_FORCE_PROBE [=]
│ Type : string
│ Defined at drivers/gpu/drm/i915/Kconfig:58
│ Prompt: Force probe i915 for selected Intel hardware IDs
│ Depends on: HAS_IOMEM [=y] && DRM [=y] && DRM_I915 [=n]
│ Location:
│ -> Device Drivers
│ -> Graphics support
│ (1) -> Direct Rendering Manager (XFree86 4.1.0 and higher DRI support) (DRM [=y])
│ -> Intel 8xx/9xx/G3x/G4x/HD Graphics (DRM_I915 [=n])
│ -> Force probe i915 for selected Intel hardware IDs (DRM_I915_FORCE_PROBE [=]) |
| Code: | Symbol: DRM_I915 [=n]
│ Type : tristate
│ Defined at drivers/gpu/drm/i915/Kconfig:2
│ Prompt: Intel 8xx/9xx/G3x/G4x/HD Graphics
│ Depends on: HAS_IOMEM [=y] && DRM [=y] && X86 [=y] && PCI [=y] && !PREEMPT_RT [=y]
│ Location:
│ -> Device Drivers
│ -> Graphics support
│ (1) -> Direct Rendering Manager (XFree86 4.1.0 and higher DRI support) (DRM [=y])
│ -> Intel 8xx/9xx/G3x/G4x/HD Graphics (DRM_I915 [=n]) |
Plz note !PREEMPT_RT.
So path to such a clue seems unaccessible on Skylake iGP.
Thks 4 ur attention, interest & support.
_________________
USE="-* ..." in /etc/portage/make.conf here, i.e. a countermeasure to portage implicit braces, belt & diaper paradigm
LT: "I've been doing a passable imitation of the Fontana di Trevi, except my medium is mucus. Sooo much mucus. " |
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Oleksa75
n00b
Joined: 18 Oct 2021
Posts: 19
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| Posted: Tue Nov 19, 2024 8:46 pm Post subject: |
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Oh, thanks alot, this section unavailable on native Gentoo sources.
I've found solution already - there is patch
| Quote: | | https://raw.githubusercontent.com/CachyOS/kernel-patches/refs/heads/master/6.12/misc/0001-rt.patch |
This patch restored (separated) section for xe driver and i915 driver with some additional configurations. |
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CaptainBlood
Advocate
Joined: 24 Jan 2010
Posts: 3870
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| Posted: Tue Nov 19, 2024 9:01 pm Post subject: |
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Nice job finding this.
Although I'd rather prefer kernel.org originated patch.
Maybe it actually is, under the hood.
not tested yet as I am in the middle of a lasting swap storm...
Thks 4 ur attention, interest & support.
_________________
USE="-* ..." in /etc/portage/make.conf here, i.e. a countermeasure to portage implicit braces, belt & diaper paradigm
LT: "I've been doing a passable imitation of the Fontana di Trevi, except my medium is mucus. Sooo much mucus. " |
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CaptainBlood
Advocate
Joined: 24 Jan 2010
Posts: 3870
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| Posted: Tue Nov 19, 2024 10:17 pm Post subject: |
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Tested working here...
Seamless upgrade from 6.11.1-rt .config to patched 6.12.0
Thks 4 ur attention, interest & support.
_________________
USE="-* ..." in /etc/portage/make.conf here, i.e. a countermeasure to portage implicit braces, belt & diaper paradigm
LT: "I've been doing a passable imitation of the Fontana di Trevi, except my medium is mucus. Sooo much mucus. " |
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