From: Mark Lord <liml@xxxxxx> Date: Sat, 31 Oct 2009 09:56:26 -0400 > Robert Hancock wrote: > .. >> This has come up before: >> http://marc.info/?l=linux-ide&m=123064513313466&w=2 >> I think this timeout should not even exist. libata has no such timeout >> (only the overall command completion timeout), and I can't find any >> reference in current ATA specs to the device being required to raise >> DRQ in any particular amount of time. > .. > > The reason for the original (20ms, then 50ms) timeout was this text > from the ATA1 specification, long since outdated: > > - Upon receipt of a Class 3 command, the drive sets BSY within 400 nsec, > sets up the sector buffer for a write operation, sets DRQ within 20 > msec, and clears BSY within 400 nsec of setting DRQ. Ok, I'd like to resolve this as follows. We had stated "at least 500msec for SSD drives" so I doubled it. This should be a pretty safe change. The only major side effect is that if the device really does hang before setting DRQ it will take a full second before we notice it. Any major objections? ide: Increase WAIT_DRQ to accomodate some CF cards and SSD drives. Based upon a patch by Philippe De Muyter, and feedback from Mark Lord and Robert Hancock. As noted by Mark Lord, the outdated ATA1 spec specifies a 20msec timeout for setting DRQ but lots of common devices overshoot this. Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> diff --git a/include/linux/ide.h b/include/linux/ide.h index e4135d6..0ec6129 100644 --- a/include/linux/ide.h +++ b/include/linux/ide.h @@ -125,8 +125,8 @@ struct ide_io_ports { * Timeouts for various operations: */ enum { - /* spec allows up to 20ms */ - WAIT_DRQ = HZ / 10, /* 100ms */ + /* spec allows up to 20ms, but CF cards and SSD drives need more */ + WAIT_DRQ = 1 * HZ, /* 1s */ /* some laptops are very slow */ WAIT_READY = 5 * HZ, /* 5s */ /* should be less than 3ms (?), if all ATAPI CD is closed at boot */ -- 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
