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Subject[PATCH] 2.6.xx: sata_mv: another critical fix
Date
This patch addresses a number of weird behaviours observed
for the sata_mv driver, by fixing an "off by one" bug in processing
of the EDMA response queue.

Basically, sata_mv was looking in the wrong place for
command results, and this produced a lot of unpredictable behaviour.

Signed-off-by: Mark Lord <mlord@pobox.com>
--- linux-2.6.16/drivers/scsi/sata_mv.c 2006-03-20 00:53:29.000000000 -0500
+++ linux/drivers/scsi/sata_mv.c 2006-03-20 23:34:32.000000000 -0500
@@ -1098,36 +1098,39 @@
* Inherited from caller.
*/
static u8 mv_get_crpb_status(struct ata_port *ap)
{
void __iomem *port_mmio = mv_ap_base(ap);
struct mv_port_priv *pp = ap->private_data;
u32 out_ptr;
+ u8 ata_status;

out_ptr = readl(port_mmio + EDMA_RSP_Q_OUT_PTR_OFS);

/* the response consumer index should be the same as we remember it */
assert(((out_ptr >> EDMA_RSP_Q_PTR_SHIFT) & MV_MAX_Q_DEPTH_MASK) ==
pp->rsp_consumer);

+ ata_status = pp->crpb[pp->rsp_consumer].flags >> CRPB_FLAG_STATUS_SHIFT;
+
/* increment our consumer index... */
pp->rsp_consumer = mv_inc_q_index(&pp->rsp_consumer);

/* and, until we do NCQ, there should only be 1 CRPB waiting */
assert(((readl(port_mmio + EDMA_RSP_Q_IN_PTR_OFS) >>
EDMA_RSP_Q_PTR_SHIFT) & MV_MAX_Q_DEPTH_MASK) ==
pp->rsp_consumer);

/* write out our inc'd consumer index so EDMA knows we're caught up */
out_ptr &= EDMA_RSP_Q_BASE_LO_MASK;
out_ptr |= pp->rsp_consumer << EDMA_RSP_Q_PTR_SHIFT;
writelfl(out_ptr, port_mmio + EDMA_RSP_Q_OUT_PTR_OFS);

/* Return ATA status register for completed CRPB */
- return (pp->crpb[pp->rsp_consumer].flags >> CRPB_FLAG_STATUS_SHIFT);
+ return ata_status;
}

/**
* mv_err_intr - Handle error interrupts on the port
* @ap: ATA channel to manipulate
*
* In most cases, just clear the interrupt and move on. However,
-
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