Commit 904c7bad authored by Mark Lord's avatar Mark Lord Committed by Jeff Garzik
Browse files

libata sata_qstor workaround for spurious interrupts 



sata_qstor workaround for spurious interrupts.

The qstor hardware generates spurious interrupts from time to time when
switching in and out of packet mode.  These eventually result in the
IRQ being disabled, which kills other devices sharing this IRQ with us.

This workaround isn't perfect, but it's about the best we can do for
this hardware.  Spurious interrupts will still happen, but won't be
logged as such, and therefore won't cause the IRQ to be inadvertently
disabled.

Signed-off-by: default avatarMark Lord <mlord@pobox.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 12ee7d3c

drivers/ata/sata_qstor.c

+21 −17
Original line number Diff line number Diff line
@@ -425,24 +425,27 @@ static inline unsigned int qs_intr_mmio(struct ata_host *host) 
		if (ap &&

		    !(ap->flags & ATA_FLAG_DISABLED)) {

			struct ata_queued_cmd *qc;

			struct qs_port_priv *pp = ap->private_data;

			if (!pp || pp->state != qs_state_mmio)

				continue;

			struct qs_port_priv *pp;

			qc = ata_qc_from_tag(ap, ap->link.active_tag);

			if (qc && (!(qc->tf.flags & ATA_TFLAG_POLLING))) {



				/* check main status, clearing INTRQ */

				u8 status = ata_check_status(ap);

				if ((status & ATA_BUSY))

					continue;

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

					ap->print_id, qc->tf.protocol, status);



				/* complete taskfile transaction */

				qc->err_mask |= ac_err_mask(status);

				ata_qc_complete(qc);

			if (!qc || !(qc->flags & ATA_QCFLAG_ACTIVE)) {

				/*

				 * The qstor hardware generates spurious

				 * interrupts from time to time when switching

				 * in and out of packet mode.

				 * There's no obvious way to know if we're

				 * here now due to that, so just ack the irq

				 * and pretend we knew it was ours.. (ugh).

				 * This does not affect packet mode.

				 */

				ata_check_status(ap);

				handled = 1;

				continue;

			}

			pp = ap->private_data;

			if (!pp || pp->state != qs_state_mmio)

				continue;

			if (!(qc->tf.flags & ATA_TFLAG_POLLING))

				handled |= ata_host_intr(ap, qc);

		}

	}

	return handled;
@@ -452,12 +455,13 @@ static irqreturn_t qs_intr(int irq, void *dev_instance) 
{

	struct ata_host *host = dev_instance;

	unsigned int handled = 0;

	unsigned long flags;



	VPRINTK("ENTER\n");



	spin_lock(&host->lock);

	spin_lock_irqsave(&host->lock, flags);

	handled  = qs_intr_pkt(host) | qs_intr_mmio(host);

	spin_unlock(&host->lock);

	spin_unlock_irqrestore(&host->lock, flags);



	VPRINTK("EXIT\n");

CRA Git | Maintained and supported by SUSTech CRA and CCSE