James Bottomley wrote: > This doesn't seem to quite work for me on a SATA-1 disc: > > sas: DOING DISCOVERY on port 1, pid:1897 > sas: sas_ata_phy_reset: Found ATA device. > ata1.00: ATA-7, max UDMA/133, 781422768 sectors: LBA48 NCQ (depth 31/32) > ata1.00: configured for UDMA/133 > scsi 2:0:1:0: Direct-Access ATA ST3400832AS 3.03 PQ: 0 > ANSI: 5 > SCSI device sdc: 781422768 512-byte hdwr sectors (400088 MB) > sdc: Write Protect is off > SCSI device sdc: drive cache: write back > SCSI device sdc: 781422768 512-byte hdwr sectors (400088 MB) > sdc: Write Protect is off > SCSI device sdc: drive cache: write back > sdc: unknown partition table > sd 2:0:1:0: Attached scsi disk sdc > sas: DONE DISCOVERY on port 1, pid:1897, result:0 > sas: command 0xf785f3c0, task 0x00000000, timed out: EH_HANDLED > sas: command 0xf785f3c0, task 0x00000000, timed out: EH_HANDLED > [...] > > It looks like the first few commands get through (read capacity, ATA > IDENTIFY etc) and it hangs up on the read for the partition table. Hm... if I put in some debug printks in the qc_issue code, I get the same symptoms. I've observed that once again we get hung up on ATA commands where the tag number > 0. I also noticed this pattern: 1. ATA command w/ tag 0 (command A) issued. 2. Command A goes out to sas-ata. 2. ATA command w/ tag 1 (command B) issued. 3. Command A completes 4. Command B goes out to sas-ata. [...] 5. Command B times out. Very odd that this all works if there are no printks. I don't see anything obvious that would suggest why this apparent race seems to happen--unless there's some conflict between issuing an ATA command while completing another one. --D - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
