Groups > linux.debian.kernel > #91317 > unrolled thread

Bug#1128567: linux-image-6.18.5+deb13-amd64: amdgpu.dc=0 causes Xorg 1:7.7+24 error "no screens found"

Started by	JohnDoeThe3rd <mk939@ymail.com>
First post	2026-02-21 11:00 +0100
Last post	2026-02-21 20:50 +0100
Articles	3 — 3 participants

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  Bug#1128567: linux-image-6.18.5+deb13-amd64: amdgpu.dc=0 causes Xorg 1:7.7+24 error "no screens found" JohnDoeThe3rd <mk939@ymail.com> - 2026-02-21 11:00 +0100
    Bug#1128567: marked as done (linux-image-6.18.5+deb13-amd64:  amdgpu.dc=0 causes Xorg 1:7.7+24 error "no screens found") "Debian Bug Tracking System" <owner@bugs.debian.org> - 2026-02-21 16:50 +0100
    Bug#1128567: linux-image-6.18.5+deb13-amd64: amdgpu.dc=0 causes Xorg 1:7.7+24 error "no screens found" Ben Hutchings <ben@decadent.org.uk> - 2026-02-21 20:50 +0100

#91317 — Bug#1128567: linux-image-6.18.5+deb13-amd64: amdgpu.dc=0 causes Xorg 1:7.7+24 error "no screens found"

From	JohnDoeThe3rd <mk939@ymail.com>
Date	2026-02-21 11:00 +0100
Subject	Bug#1128567: linux-image-6.18.5+deb13-amd64: amdgpu.dc=0 causes Xorg 1:7.7+24 error "no screens found"
Message-ID	<MqRWh-2dLi-1@gated-at.bofh.it>

Package: src:linux
Version: 6.18.5-1~bpo13+1
Severity: important
X-Debbugs-Cc: mk939@ymail.com


Greetings.

When the Kernel command-line parameter 'amdgpu.dc=0' is used, the screen resolution
(and TTY font) does not change on boot (i.e. stays whatever was used in GRUB).
The boot messages stop updating and a few seconds after, the screen turns off.

Excerpt from 'journalctl --boot=PREVIOUS_BOOT_HASH':
---
Feb 21 08:54:18 x7 systemd[1]: lightdm.service: Main process exited, code=exited, status=1/FAILURE
Feb 21 08:54:18 x7 systemd[1]: lightdm.service: Failed with result 'exit-code'.
Feb 21 08:54:18 x7 systemd[1]: lightdm.service: Triggering OnFailure= dependencies.
---

Exerpt from '/var/log/Xorg.0.log.old'
---
[    13.170] (II) AMDGPU(0): glamor X acceleration enabled on AMD Radeon RX 570 Series (radeonsi, polaris10, ACO, DRM 3.64, 6.18.5+deb13-amd64)
[    13.170] (II) AMDGPU(0): glamor detected, initialising EGL layer.
[    13.170] (==) AMDGPU(0): TearFree property default: auto
[    13.170] (==) AMDGPU(0): VariableRefresh: disabled
[    13.170] (==) AMDGPU(0): AsyncFlipSecondaries: disabled
[    13.170] (II) AMDGPU(0): KMS Pageflipping: enabled
[    13.170] (WW) AMDGPU(0): No outputs definitely connected, trying again...
[    13.170] (WW) AMDGPU(0): Unable to find connected outputs - setting 1024x768 initial framebuffer
[    13.170] (II) AMDGPU(0): mem size init: gart size :1f0bb8000 vram size: s:fefd0000 visible:fad0000
[    13.170] (==) AMDGPU(0): DPI set to (96, 96)
[    13.170] (==) AMDGPU(0): Using gamma correction (1.0, 1.0, 1.0)
[    13.170] (II) Loading sub module "ramdac"
[    13.170] (II) LoadModule: "ramdac"
[    13.170] (II) Module "ramdac" already built-in
[    13.170] (EE) AMDGPU(0): No modes.
[    13.171] (II) UnloadModule: "amdgpu"
[    13.171] (II) UnloadSubModule: "glamoregl"
[    13.171] (II) Unloading glamoregl
[    13.171] (EE) Screen(s) found, but none have a usable configuration.
[    13.171] (EE)
Fatal server error:
[    13.171] (EE) no screens found(EE)
[    13.171] (EE)
---
Full log: https://paste.debian.net/hidden/6f585df9 (expires: 2026-05-22 09:39:21 UTC+0)


Manual bisect results:

- 6.12.63+deb13-amd64 --> GOOD
- 6.16.7+deb14-amd64  --> GOOD
- 6.17.13+deb13-amd64 --> GOOD
- 6.18.5+deb13-amd64  --> BAD

Removing the paramameter 'amdgpu.dc=0' does bring back Xorg to a working state.
However, this should not break Xorg at all. Currently I need this parameter such that
adjusting the brightness is possible using the 'ddcutil' application.



-- Package-specific info:
** Kernel log: boot messages should be attached

** Model information
sys_vendor: Gigabyte Technology Co., Ltd.
product_name: Z87-HD3
product_version: To be filled by O.E.M.
chassis_vendor: Gigabyte Technology Co., Ltd.
chassis_version: To Be Filled By O.E.M.
bios_vendor: American Megatrends Inc.
bios_version: F8
board_vendor: Gigabyte Technology Co., Ltd.
board_name: Z87-HD3
board_version: To be filled by O.E.M.

** Configuration for modprobe:
blacklist microcode
blacklist arkfb
blacklist aty128fb
blacklist atyfb
blacklist radeonfb
blacklist cirrusfb
blacklist cyber2000fb
blacklist kyrofb
blacklist matroxfb_base
blacklist mb862xxfb
blacklist neofb
blacklist pm2fb
blacklist pm3fb
blacklist s3fb
blacklist savagefb
blacklist sisfb
blacklist tdfxfb
blacklist tridentfb
blacklist vt8623fb
blacklist microcode
options snd_pcsp index=-2
options cx88_alsa index=-2
options snd_atiixp_modem index=-2
options snd_intel8x0m index=-2
options snd_via82xx_modem index=-2
options md_mod start_ro=1
options bonding max_bonds=0
options dummy numdummies=0
options ifb numifbs=0

** PCI devices:
00:16.0 Communication controller [0780]: Intel Corporation 8 Series/C220 Series Chipset Family MEI Controller #1 [8086:8c3a] (rev 04)
	Subsystem: Gigabyte Technology Co., Ltd Device [1458:1c3a]
	Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 0
	Interrupt: pin A routed to IRQ 37
	IOMMU group: 3
	Region 0: Memory at f7f1a000 (64-bit, non-prefetchable) [size=16]
	Capabilities: <access denied>
	Kernel driver in use: mei_me
	Kernel modules: mei_me

00:1c.0 PCI bridge [0604]: Intel Corporation 8 Series/C220 Series Chipset Family PCI Express Root Port #1 [8086:8c10] (rev d5) (prog-if 00 [Normal decode])
	Subsystem: Gigabyte Technology Co., Ltd Device [1458:5001]
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 0, Cache Line Size: 64 bytes
	Interrupt: pin A routed to IRQ 26
	IOMMU group: 6
	Bus: primary=00, secondary=02, subordinate=02, sec-latency=0
	I/O behind bridge: [disabled] [16-bit]
	Memory behind bridge: [disabled] [32-bit]
	Prefetchable memory behind bridge: [disabled] [64-bit]
	Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- <SERR- <PERR-
	BridgeCtl: Parity- SERR+ NoISA- VGA- VGA16+ MAbort- >Reset- FastB2B-
		PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn-
	Capabilities: <access denied>
	Kernel driver in use: pcieport
	Kernel modules: shpchp

00:1c.2 PCI bridge [0604]: Intel Corporation 8 Series/C220 Series Chipset Family PCI Express Root Port #3 [8086:8c14] (rev d5) (prog-if 00 [Normal decode])
	Subsystem: Gigabyte Technology Co., Ltd Device [1458:5001]
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 0, Cache Line Size: 64 bytes
	Interrupt: pin C routed to IRQ 27
	IOMMU group: 7
	Bus: primary=00, secondary=03, subordinate=03, sec-latency=0
	I/O behind bridge: d000-dfff [size=4K] [16-bit]
	Memory behind bridge: f7d00000-f7dfffff [size=1M] [32-bit]
	Prefetchable memory behind bridge: f0300000-f03fffff [size=1M] [32-bit]
	Secondary status: 66MHz- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- <SERR- <PERR-
	BridgeCtl: Parity- SERR+ NoISA- VGA- VGA16+ MAbort- >Reset- FastB2B-
		PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn-
	Capabilities: <access denied>
	Kernel driver in use: pcieport
	Kernel modules: shpchp

00:1f.0 ISA bridge [0601]: Intel Corporation Z87 Express LPC Controller [8086:8c44] (rev 05)
	Subsystem: Gigabyte Technology Co., Ltd Device [1458:5001]
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 0
	IOMMU group: 10
	Capabilities: <access denied>
	Kernel driver in use: lpc_ich
	Kernel modules: lpc_ich

00:1f.3 SMBus [0c05]: Intel Corporation 8 Series/C220 Series Chipset Family SMBus Controller [8086:8c22] (rev 05)
	Subsystem: Gigabyte Technology Co., Ltd Device [1458:5001]
	Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
	Status: Cap- 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Interrupt: pin C routed to IRQ 18
	IOMMU group: 10
	Region 0: Memory at f7f15000 (64-bit, non-prefetchable) [size=256]
	Region 4: I/O ports at f000 [size=32]
	Kernel driver in use: i801_smbus
	Kernel modules: i2c_i801

01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere [Radeon RX 470/480/570/570X/580/580X/590] [1002:67df] (rev ef) (prog-if 00 [VGA controller])
	Subsystem: ASUSTeK Computer Inc. Device [1043:04c2]
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 0, Cache Line Size: 64 bytes
	Interrupt: pin A routed to IRQ 36
	IOMMU group: 1
	Region 0: Memory at e0000000 (64-bit, prefetchable) [size=256M]
	Region 2: Memory at f0000000 (64-bit, prefetchable) [size=2M]
	Region 4: I/O ports at e000 [size=256]
	Region 5: Memory at f7e00000 (32-bit, non-prefetchable) [size=256K]
	Expansion ROM at 000c0000 [disabled] [size=128K]
	Capabilities: <access denied>
	Kernel driver in use: amdgpu
	Kernel modules: amdgpu

01:00.1 Audio device [0403]: Advanced Micro Devices, Inc. [AMD/ATI] Ellesmere HDMI Audio [Radeon RX 470/480 / 570/580/590] [1002:aaf0]
	Subsystem: ASUSTeK Computer Inc. Device [1043:aaf0]
	Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
	Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 0, Cache Line Size: 64 bytes
	Interrupt: pin B routed to IRQ 38
	IOMMU group: 1
	Region 0: Memory at f7e60000 (64-bit, non-prefetchable) [size=16K]
	Capabilities: <access denied>
	Kernel driver in use: snd_hda_intel
	Kernel modules: snd_hda_intel


** USB devices:
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:8000 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 002: ID 8087:8008 Intel Corp. Integrated Rate Matching Hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub


-- System Information:
Debian Release: 13.3
  APT prefers stable
  APT policy: (500, 'stable'), (500, 'oldstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 6.18.5+deb13-amd64 (SMP w/4 CPU threads; PREEMPT)
Locale: LANG=de_CH.UTF-8, LC_CTYPE=de_CH.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages linux-image-6.18.5+deb13-amd64 depends on:
ii  initramfs-tools [linux-initramfs-tool]  0.148.3
ii  kmod                                    34.2-2
ii  linux-base                              4.12
ii  linux-base-6.18.5+deb13-amd64           6.18.5-1~bpo13+1

Versions of packages linux-image-6.18.5+deb13-amd64 recommends:
ii  apparmor  4.1.0-1

Versions of packages linux-image-6.18.5+deb13-amd64 suggests:
pn  debian-kernel-handbook  <none>
ii  firmware-linux-free     20241210-2
ii  grub-efi-amd64          2.12-9
pn  linux-doc-6.18          <none>

Versions of packages linux-image-6.18.5+deb13-amd64 is related to:
ii  firmware-amd-graphics      20250410-2
ii  firmware-atheros           20250410-2
ii  firmware-bnx2              20250410-2
ii  firmware-bnx2x             20250410-2
ii  firmware-brcm80211         20250410-2
ii  firmware-cavium            20250410-2
ii  firmware-cirrus            20250410-2
ii  firmware-intel-graphics    20250410-2
ii  firmware-intel-misc        20250410-2
ii  firmware-intel-sound       20250410-2
ii  firmware-ipw2x00           20250410-2
ii  firmware-ivtv              20250410-2
ii  firmware-iwlwifi           20250410-2
ii  firmware-libertas          20250410-2
ii  firmware-marvell-prestera  20250410-2
ii  firmware-mediatek          20250410-2
ii  firmware-misc-nonfree      20250410-2
ii  firmware-myricom           20250410-2
ii  firmware-netronome         20250410-2
ii  firmware-netxen            20250410-2
ii  firmware-nvidia-graphics   20250410-2
pn  firmware-qcom-soc          <none>
ii  firmware-qlogic            20250410-2
ii  firmware-realtek           20250410-2
pn  firmware-samsung           <none>
ii  firmware-siano             20250410-2
pn  firmware-ti-connectivity   <none>
pn  xen-hypervisor             <none>

-- no debconf information

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#91325 — Bug#1128567: marked as done (linux-image-6.18.5+deb13-amd64: amdgpu.dc=0 causes Xorg 1:7.7+24 error "no screens found")

From	"Debian Bug Tracking System" <owner@bugs.debian.org>
Date	2026-02-21 16:50 +0100
Subject	Bug#1128567: marked as done (linux-image-6.18.5+deb13-amd64: amdgpu.dc=0 causes Xorg 1:7.7+24 error "no screens found")
Message-ID	<MqXoZ-2hhm-7@gated-at.bofh.it>
In reply to	#91317

[Multipart message — attachments visible in raw view] — view raw

Your message dated Sat, 21 Feb 2026 16:38:50 +0100
with message-id <b696bee0d148d40e9e4069eedceb4ebc12083557.camel@decadent.org.uk>
and subject line Re: Bug#1128567: linux-image-6.18.5+deb13-amd64: amdgpu.dc=0 causes Xorg 1:7.7+24 error "no screens found"
has caused the Debian Bug report #1128567,
regarding linux-image-6.18.5+deb13-amd64: amdgpu.dc=0 causes Xorg 1:7.7+24 error "no screens found"
to be marked as done.

This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.

(NB: If you are a system administrator and have no idea what this
message is talking about, this may indicate a serious mail system
misconfiguration somewhere. Please contact owner@bugs.debian.org
immediately.)


-- 
1128567: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1128567
Debian Bug Tracking System
Contact owner@bugs.debian.org with problems

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#91329

From	Ben Hutchings <ben@decadent.org.uk>
Date	2026-02-21 20:50 +0100
Message-ID	<Mr19f-2jLu-7@gated-at.bofh.it>
In reply to	#91317

[Multipart message — attachments visible in raw view] — view raw

On Sat, 2026-02-21 at 17:08 +0100, JohnDoeThe3rd wrote:
> My particular use-case is such that 'ddcutil' can issue commands over 
> the Display Data Channel (DDC), which does not work as 
> long CONFIG_DRM_AMD_DC is enabled.
> 
> Or do you mean that the 'amdgpu.dc' parameter deprecated? If not, then 
> it's a regression that should be fixed.

I can't speak for the amdgpu developers, but they seem to be already
very busy with bugs in the default driver configuration.  Since the
Display Core code has been around since 2017, I don't think it's
reasonable to expect that the old code path continues to be supported
for GPUs that Display Core supports.

It may be more productive to report the problem with ddcutil in Display
Core.

For what it's worth, ddcutil works for me with amdgpu and a monitor
connected via HDMI/DVI.  This computer has a slightly newer generation
of GPU than yours, though.

Ben.

-- 
Ben Hutchings
Who are all these weirdos? - David Bowie, on joining IRC

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csiph-web

Bug#1128567: linux-image-6.18.5+deb13-amd64: amdgpu.dc=0 causes Xorg 1:7.7+24 error "no screens found"

Contents

#91317 — Bug#1128567: linux-image-6.18.5+deb13-amd64: amdgpu.dc=0 causes Xorg 1:7.7+24 error "no screens found"

#91325 — Bug#1128567: marked as done (linux-image-6.18.5+deb13-amd64: amdgpu.dc=0 causes Xorg 1:7.7+24 error "no screens found")

#91329