On Wed, Jun 2, 2010 at 10:00 PM, Matthew Garrett <mjg59@xxxxxxxxxxxxx> wrote:
> 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@xxxxxxxxxxxxx
If it's helpful, attached are the dmesg output following a normal boot
and one with the hang.
The only difference in the kernel used for those two boots is that the
return statement in ahci_start_engine following the call to
ahci_is_device_present is commented out for the normal boot case.
When the return statement is active, the 30 second hang occurs.
Marc
Attachment:
bad_ahci_dmesg
Description: Binary data
Attachment:
normal_ahci_dmesg
Description: Binary data
