REGRESSION ThinkPad T410 fails to see AHCI device on boot with wily SRU kernels

[Stefano Rivera]

We have a set of ThinkPads (T410 and T540p) that are failing to boot (not locating their root fs device) with post-release kernels.

The AHCI adaptor (0000:00:1f.5) simply isn't visible in /sys/bus/pci/devices/

The problem is apparent in 4.2.0.25-30, and not in 4.2.0-16.19

If the SATA device mode is changed from AHCI to IDE emulation, then they reliably boot.

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: linux-image-4.2.0-16-generic 4.2.0-16.19
ProcVersionSignature: Ubuntu 4.2.0-16.19-generic 4.2.3
Uname: Linux 4.2.0-16-generic x86_64
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
CurrentDesktop: Unity
Date: Wed Jan 27 16:41:50 2016
HibernationDevice: RESUME=UUID=185cef3a-6688-4034-a910-4f6ecdea2c20
IwConfig:
 enp0s25 no wireless extensions.

 lo no wireless extensions.

 enx8a549328aae7 no wireless extensions.
MachineType: LENOVO 253725M
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-16-generic root=UUID=e5bcc2d8-520b-4648-9a08-0cc1d65152fd ro BOOTIF=01-f0-de-f1-49-05-1b quiet splash crashkernel=384M-:128M
RelatedPackageVersions:
 linux-restricted-modules-4.2.0-16-generic N/A
 linux-backports-modules-4.2.0-16-generic N/A
 linux-firmware 1.149.3
SourcePackage: linux
UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev'
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/01/2011
dmi.bios.vendor: LENOVO
dmi.bios.version: 6IET75WW (1.35 )
dmi.board.name: 253725M
dmi.board.vendor: LENOVO
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.modalias: dmi:bvnLENOVO:bvr6IET75WW(1.35):bd02/01/2011:svnLENOVO:pn253725M:pvrThinkPadT410:rvnLENOVO:rn253725M:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
dmi.product.name: 253725M
dmi.product.version: ThinkPad T410
dmi.sys.vendor: LENOVO

[Stefano Rivera (stefanor)]

> The AHCI adaptor (0000:00:1f.5) simply isn't visible in /sys/bus/pci/devices/

hrm, it seems that was wrong. The adaptor is 1f.2 and is now visible (although I swear it wasn't, earlier). But ahci didn't bind to it.

[Brad Figg (brad-figg)]

This change was made by a bot.

[Stefano Rivera (stefanor)]

Nope, it was a fucked initramfs, due to a crazy local udev rule. That took way too long to debug.