[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: Albert Lee <albertcc@tw.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index d68f5d5..59cb129 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -3587,12 +3587,6 @@
*/
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 @@
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 @@
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 @@
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 &&