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Commit e141d999 authored by Tejun Heo's avatar Tejun Heo Committed by Jeff Garzik
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libata: limit post SRST nsect/lbal wait to ~100ms 



After SRST, libata used to wait for nsect/lbal to be set to 1/1 for
the slave device.  However, some ATAPI devices don't set nsect/lbal
after SRST and the wait itself isn't too useful as we're gonna wait
for !BSY right after that anyway.

Before reset-seq update, nsect/lbal wait failure used to be ignored
and caused 30sec delay during detection.  After reset-seq, all
timeouts are considered error conditions making libata fail to detect
such ATAPI devices.

This patch limits nsect/lbal wait to around 100ms.  This should give
acceptable behavior to such ATAPI devices while not disturbing the
heavily used code path too much.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 5acd50f6

drivers/ata/libata-core.c

+19 −13
Original line number Diff line number Diff line
@@ -3061,22 +3061,28 @@ static int ata_bus_post_reset(struct ata_port *ap, unsigned int devmask, 
		}

	}



	/* if device 1 was found in ata_devchk, wait for

	 * register access, then wait for BSY to clear

	/* if device 1 was found in ata_devchk, wait for register

	 * access briefly, then wait for BSY to clear.

	 */

	while (dev1) {

		u8 nsect, lbal;

	if (dev1) {

		int i;



		ap->ops->dev_select(ap, 1);



		/* Wait for register access.  Some ATAPI devices fail

		 * to set nsect/lbal after reset, so don't waste too

		 * much time on it.  We're gonna wait for !BSY anyway.

		 */

		for (i = 0; i < 2; i++) {

			u8 nsect, lbal;



			nsect = ioread8(ioaddr->nsect_addr);

			lbal = ioread8(ioaddr->lbal_addr);

			if ((nsect == 1) && (lbal == 1))

				break;

		if (time_after(jiffies, deadline))

			return -EBUSY;

			msleep(50);	/* give drive a breather */

		}

	if (dev1) {



		rc = ata_wait_ready(ap, deadline);

		if (rc) {

			if (rc != -ENODEV)