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Commit 2d3b8eea authored by Albert Lee's avatar Albert Lee Committed by Tejun Heo
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libata: workaround DRQ=1 ERR=1 for ATAPI tape drives 



After an error condition, some ATAPI tape drives set DRQ=1 together
with ERR=1 when asking the host to transfer the CDB of the next packet
command (i.e. request sense).  This patch, a revised version of
Alan/Mark's previous patch, adds ATA_HORKAGE_STUCK_ERR to workaround
the problem by ignoring the ERR bit and proceed sending the CDB.

Signed-off-by: default avatarAlbert Lee <albertcc@tw.ibm.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Mark Lord <liml@rtr.ca>
Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
parent 21bef6dd

drivers/ata/libata-core.c

+13 −5
Original line number Diff line number Diff line
@@ -5415,12 +5415,20 @@ int ata_hsm_move(struct ata_port *ap, struct ata_queued_cmd *qc, 
		 * let the EH abort the command or reset the device.

		 */

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

			ata_port_printk(ap, KERN_WARNING, "DRQ=1 with device "

					"error, dev_stat 0x%X\n", status);

			/* Some ATAPI tape drives forget to clear the ERR bit

			 * when doing the next command (mostly request sense).

			 * We ignore ERR here to workaround and proceed sending

			 * the CDB.

			 */

			if (!(qc->dev->horkage & ATA_HORKAGE_STUCK_ERR)) {

				ata_port_printk(ap, KERN_WARNING,

						"DRQ=1 with device error, "

						"dev_stat 0x%X\n", status);

				qc->err_mask |= AC_ERR_HSM;

				ap->hsm_task_state = HSM_ST_ERR;

				goto fsm_start;

			}

		}



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

		 * During the state transition, interrupt handler shouldn't

include/linux/libata.h

+1 −0
Original line number Diff line number Diff line
@@ -340,6 +340,7 @@ enum { 
	ATA_HORKAGE_HPA_SIZE	= (1 << 6),	/* native size off by one */

	ATA_HORKAGE_IPM		= (1 << 7),	/* Link PM problems */

	ATA_HORKAGE_IVB		= (1 << 8),	/* cbl det validity bit bugs */

	ATA_HORKAGE_STUCK_ERR	= (1 << 9),	/* stuck ERR on next PACKET */



	 /* DMA mask for user DMA control: User visible values; DO NOT

	    renumber */