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Commit 71601958 authored by Albert Lee's avatar Albert Lee Committed by Jeff Garzik
Browse files

[PATCH] libata-dev: fix the device err check sequence (respin) 



Current irq-pio checks ERR bit and stops on ERR before it does anything else.
This behavior doesn't look right.
The DRQ bit should take higher precedence than the ERR bit.

Changes:
- Let the HSM do the data transfer whenever the
  device asks for DRQ bit, even if the ERR bit is set.
- For DRQ=1 ERR=1, don't trust the data

Signed-off-by: default avatarAlbert Lee <albertcc@tw.ibm.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 999bb6f4

drivers/scsi/libata-core.c

+38 −6
Original line number Diff line number Diff line
@@ -3587,12 +3587,6 @@ static int ata_hsm_move(struct ata_port *ap, struct ata_queued_cmd *qc, 
	 */

	WARN_ON(in_wq != ata_hsm_ok_in_wq(ap, qc));



	/* check error */

	if (unlikely(status & (ATA_ERR | ATA_DF))) {

		qc->err_mask |= AC_ERR_DEV;

		ap->hsm_task_state = HSM_ST_ERR;

	}



fsm_start:

	DPRINTK("ata%u: protocol %d task_state %d (dev_stat 0x%X)\n",

		ap->id, qc->tf.protocol, ap->hsm_task_state, status);
@@ -3615,6 +3609,17 @@ static int ata_hsm_move(struct ata_port *ap, struct ata_queued_cmd *qc, 
			goto fsm_start;

		}



		/* Device should not ask for data transfer (DRQ=1)

		 * when it finds something wrong.

		 * Anyway, we respect DRQ here and let HSM go on

		 * without changing hsm_task_state to HSM_ST_ERR.

		 */

		if (unlikely(status & (ATA_ERR | ATA_DF))) {

			printk(KERN_WARNING "ata%d: DRQ=1 with device error, dev_stat 0x%X\n",

			       ap->id, status);

			qc->err_mask |= AC_ERR_DEV;

		}



		/* Send the CDB (atapi) or the first data block (ata pio out).

		 * During the state transition, interrupt handler shouldn't

		 * be invoked before the data transfer is complete and
@@ -3657,6 +3662,17 @@ static int ata_hsm_move(struct ata_port *ap, struct ata_queued_cmd *qc, 
				goto fsm_start;

			}



			/* Device should not ask for data transfer (DRQ=1)

			 * when it finds something wrong.

			 * Anyway, we respect DRQ here and let HSM go on

			 * without changing hsm_task_state to HSM_ST_ERR.

			 */

			if (unlikely(status & (ATA_ERR | ATA_DF))) {

				printk(KERN_WARNING "ata%d: DRQ=1 with device error, dev_stat 0x%X\n",

				       ap->id, status);

				qc->err_mask |= AC_ERR_DEV;

			}



			atapi_pio_bytes(qc);



			if (unlikely(ap->hsm_task_state == HSM_ST_ERR))
@@ -3672,6 +3688,22 @@ static int ata_hsm_move(struct ata_port *ap, struct ata_queued_cmd *qc, 
				goto fsm_start;

			}



			/* Some devices may ask for data transfer (DRQ=1)

			 * alone with ERR=1 for PIO reads.

			 * We respect DRQ here and let HSM go on without

			 * changing hsm_task_state to HSM_ST_ERR.

			 */

			if (unlikely(status & (ATA_ERR | ATA_DF))) {

				/* For writes, ERR=1 DRQ=1 doesn't make

				 * sense since the data block has been

				 * transferred to the device.

				 */

				WARN_ON(qc->tf.flags & ATA_TFLAG_WRITE);



				/* data might be corrputed */

				qc->err_mask |= AC_ERR_DEV;

			}



			ata_pio_sectors(qc);



			if (ap->hsm_task_state == HSM_ST_LAST &&