FC6 system stalls (kernel == 2.6.20-1.2952.fc6)

[Jeffrey Ross]

Dean S. Messing wrote:
> I'm experiencing strange "stalls" (lockups) in my system that last for
> half a minute or so.  Can anybody give me a clue for how to fix this?
>
> I've discovered that they coincide with these messages being
> written to /var/log/messges:
>
> Jun  5 15:07:23 localhost kernel: ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x2 frozen
> Jun  5 15:07:23 localhost kernel: ata2.00: cmd a0/01:00:00:00:00/00:00:00:00:00/a0 tag 0 cdb 0x4a data 8 in
> Jun  5 15:07:23 localhost kernel:          res 40/00:03:00:00:00/00:00:00:00:00/a0 Emask 0x4 (timeout)
> Jun  5 15:07:30 localhost kernel: ata2: port is slow to respond, please be patient (Status 0xd0)
> Jun  5 15:07:53 localhost kernel: ata2: port failed to respond (30 secs, Status 0xd0)
> Jun  5 15:07:53 localhost kernel: ata2: soft resetting port
> Jun  5 15:07:54 localhost kernel: ata2.00: configured for UDMA/33
> Jun  5 15:07:54 localhost kernel: ata2: EH complete
>
> The system is a laptop with one disk (/dev/sda) and one CDRW/DVD
> (/dev/scd0).  I think the messages above refer to the CDRW/DVD.
>
> I have "combined_mode=libata" as a boot parameter so that the CDRW/DVD
> appears as a SCSI device.  From some googling I've learned that the
> messages may be due to the new "libata" stuff in the kernel (which I
> don't pretend to understand).
>
> Following are some more, possibly relevant, messages from when
> I booted the system last evening.
>
> .....<snip>.....
> kernel: ata1: SATA max UDMA/133 cmd 0x1F0 ctl 0x3F6 bmdma 0xBFA0 irq 14
> kernel: ata2: PATA max UDMA/100 cmd 0x170 ctl 0x376 bmdma 0xBFA8 irq 15
> kernel: scsi0 : ata_piix
> kernel: ata1.00: ATA-6, max UDMA/100, 156301488 sectors: LBA48 
> kernel: ata1.00: ata1: dev 0 multi count 8
> kernel: ata1.00: applying bridge limits
> kernel: ata1.00: configured for UDMA/100
> kernel: scsi1 : ata_piix
> kernel: ata2.00: ATAPI, max UDMA/33
> kernel: ata2.00: configured for UDMA/33
> kernel: scsi 0:0:0:0: Direct-Access     ATA      Hitachi HTS54108 MB4O PQ: 0 ANSI: 5
> kernel: SCSI device sda: 156301488 512-byte hdwr sectors (80026 MB)
> kernel: sda: Write Protect is off
> kernel: SCSI device sda: write cache: enabled, read cache: enabled, doesn't support DPO or FUA
> kernel: SCSI device sda: 156301488 512-byte hdwr sectors (80026 MB)
> kernel: sda: Write Protect is off
> kernel: SCSI device sda: write cache: enabled, read cache: enabled, doesn't support DPO or FUA
> kernel:  sda: sda1 sda2 < sda5 sda6 sda7 sda8 sda9 sda10 sda11 >
> kernel: sd 0:0:0:0: Attached scsi disk sda
> kernel: scsi 1:0:0:0: CD-ROM            PHILIPS  CDRW/DVD SCB5265 TD15 PQ: 0 ANSI: 5
> .....<snip>.....
>
> Dean
>
>   
Dean, I am also experiencing lockups on Fedora 7 and I also get the same 
messages in the logs.  Question did "combined_mode=libata" resolve the 
issue for now?

thanks, Jeff