Public bug reported:
Summary: External USB disk detected but fails to initialize as block
device on AMD B450 (Toshiba USB 3.0 bridge)
Problem description:
After boot or reconnect, an external Toshiba USB 3.0 drive is detected
by the USB subsystem, but fails to initialize as a usable block device.
The kernel log shows that the USB bridge is recognized correctly, but
the disk does not respond properly to SCSI commands. The drive attempts
to spin up, then fails with capacity read errors and reports zero
logical blocks.
This results in:
* no /dev/sdX device
* no mount
* no automount notification
The issue appears related to USB initialization timing and/or controller
interaction on AMD 400-series chipsets.
Hardware:
MSI B450I Gaming mainboard (AMD Ryzen platform)
Software:
Ubuntu with kernel 6.8.0-101-generic
Steps to reproduce:
1. Connect the external Toshiba USB drive
2. Boot the system or reconnect the drive
3. Obse
ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: linux-image-6.8.0-101-generic 6.8.0-101.101
ProcVersionSignature: Ubuntu 6.8.0-101.101-generic 6.8.12
Uname: Linux 6.8.0-101-generic x86_64
ApportVersion: 2.28.1-0ubuntu3.8
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC1: newcomer01 2169 F.... wireplumber
/dev/snd/controlC2: newcomer01 2169 F.... wireplumber
/dev/snd/controlC0: newcomer01 2169 F.... wireplumber
/dev/snd/seq: newcomer01 2165 F.... pipewire
CRDA: N/A
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Thu Feb 26 14:23:49 2026
InstallationDate: Installed on 2025-07-13 (228 days ago)
InstallationMedia: Ubuntu 22.04.4 LTS "Jammy Jellyfish" - Release amd64
(20240220)
MachineType: Micro-Star International Co., Ltd. MS-7A40
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.8.0-101-generic
root=UUID=d068eac6-c411-4f4f-8553-f85206207b0e ro quiet splash reboot=pci
vt.handoff=7
PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No
PulseAudio daemon running, or not running as session daemon.
RelatedPackageVersions:
linux-restricted-modules-6.8.0-101-generic N/A
linux-backports-modules-6.8.0-101-generic N/A
linux-firmware 20240318.git3b128b60-0ubuntu2.25
SourcePackage: linux
UpgradeStatus: Upgraded to noble on 2025-07-13 (228 days ago)
dmi.bios.date: 05/20/2019
dmi.bios.release: 5.14
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: A.72
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: B450I GAMING PLUS AC (MS-7A40)
dmi.board.vendor: Micro-Star International Co., Ltd.
dmi.board.version: 2.0
dmi.chassis.asset.tag: To be filled by O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: Micro-Star International Co., Ltd.
dmi.chassis.version: 2.0
dmi.modalias:
dmi:bvnAmericanMegatrendsInc.:bvrA.72:bd05/20/2019:br5.14:svnMicro-StarInternationalCo.,Ltd.:pnMS-7A40:pvr2.0:rvnMicro-StarInternationalCo.,Ltd.:rnB450IGAMINGPLUSAC(MS-7A40):rvr2.0:cvnMicro-StarInternationalCo.,Ltd.:ct3:cvr2.0:skuTobefilledbyO.E.M.:
dmi.product.family: To be filled by O.E.M.
dmi.product.name: MS-7A40
dmi.product.sku: To be filled by O.E.M.
dmi.product.version: 2.0
dmi.sys.vendor: Micro-Star International Co., Ltd.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug noble wayland-session
** Attachment added: "all terminal outputs while debugging"
https://bugs.launchpad.net/bugs/2142753/+attachment/5948714/+files/debug.txt
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https://bugs.launchpad.net/bugs/2142753
Title:
External USB disk detected but fails to initialize as block device on
AMD B450 (Toshiba USB 3.0 bridge)
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