Re: Hang during boot, bisected to commit 96d60303fd

[Matthew Garrett <mjg59@srcf.ucam.org>]

On Wed, Jun 02, 2010 at 09:49:27PM -0400, Marc Dionne wrote:
>    Since somewhere early in the 2.6.35 merge window I've been seeing a hang
>    during boot.  The hang last roughly 30 seconds and is followed by this:
> 
>    ata4.00: exception Emask 0x0 SAct 0x1 SErr 0x0 action 0x6 frozen
>    ata4.00: failed command: READ FPDMA QUEUED
>    ata4.00: cmd 60/08:00:00:00:00/00:00:00:00:00/40 tag 0 ncq 4096 in
>             res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
>    ata4.00: status: { DRDY }
>    ata4: hard resetting link
>    ahci_is_device_present: status is: 80
>    ahci_is_device_present: status(2) is: 3
>    ata4: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
>    ata4.00: configured for UDMA/133
>    ata4.00: device reported invalid CHS sector 0
>    ata4: EH complete
> 
>    The system works normally once booted.  I had some time to do a bisect
>    today and it cleanly ended up pointing to this commit:
>        96d60303fd: ahci: Turn off DMA engines when there's no device attached
> 
>    Reverting the commit makes the system boot cleanly as before.  System has
>    an Intel ICH10 based board, in AHCI mode, disk is an Intel X25M SSD.

Hm, interesting. Jeff, any immediate ideas? I don't see this behaviour 
on my ICH10. Is there actually a device on ata4?

-- 
Matthew Garrett | mjg59@srcf.ucam.org