[cc'ing Jens, hello] Mark Lord wrote: > Tejun Heo wrote: >> Both ATA and ATAPI devices used the default timeouts defined by SCSI >> high level driver. For both disks and ODDs, it was 30secs, which was >> way too long for disks. This patch makes most ATA commands time out >> after 7secs - the de facto ATA command timeout, while leaving ATAPI >> timeout at 30secs. > > Good patch, LONG overdue. > > But 7 seconds is too short. I have drives here now that > take slightly more than 7 seconds to report media errors. > > With this patch, libata will timeout/reset the drive just before > it had a chance to tell us why it was taking too long. > > The result would be that we might lose data unnecessarily, > especially in combination with the current SCSI policy of > blindly failing the entire request when only one sector was bad. Timeout doesn't indicate media error, so SCSI will retry the command several times. So, those two don't interact. > I've used 10 second timeouts with 100% success over the past 14 years, > which allows just enough margin (+2) for drives to finish their internal > retries and report back. > > NACK to 7, ACK to 10 seconds. Hmmm... I don't care whether 7 or 10. The biggest reason I chose 7 was because somebody told me that that's the de-facto default ATA command timeout && the other os is using it. I faintly remembers that it was yourself or Jens. Or I might be just imagining things again. :-) Jens, what do you think about this? Thanks. -- tejun - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
