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
