[PATCH] libata-dev: handle DRQ=1 ERR=1 (revised)

Handle DRQ=1 ERR=1 situation. Revised according to what IDE try_to_flush_leftover_data() does.

Changes:
 - For ATA PIO writes and ATAPI devices, just stop the HSM and let EH handle it.
 - For ATA PIO reads, read only one block of junk data and then let EH handle it.

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 32 insertions, 14 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 6fc25f60db97..da13deccc0e0 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -3640,13 +3640,16 @@ 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.
+                 * We ignore DRQ here and stop the HSM by
+                 * changing hsm_task_state to HSM_ST_ERR and
+                 * let the EH abort the command or reset the device.
                  */
                 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;
+                        ap->hsm_task_state = HSM_ST_ERR;
+                        goto fsm_start;
                 }
 
                 /* Send the CDB (atapi) or the first data block (ata pio out).
@@ -3693,13 +3696,16 @@ 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.
+                         * We ignore DRQ here and stop the HSM by
+                         * changing hsm_task_state to HSM_ST_ERR and
+                         * let the EH abort the command or reset the device.
                          */
                         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;
+                                ap->hsm_task_state = HSM_ST_ERR;
+                                goto fsm_start;
                         }
 
                         atapi_pio_bytes(qc);
@@ -3717,20 +3723,32 @@ fsm_start:
                                 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.
+                        /* For PIO reads, some devices may ask for
+                         * data transfer (DRQ=1) alone with ERR=1.
+                         * We respect DRQ here and transfer one
+                         * block of junk data before changing the
+                         * hsm_task_state to HSM_ST_ERR.
+                         *
+                         * For PIO writes, ERR=1 DRQ=1 doesn't make
+                         * sense since the data block has been
+                         * transferred to the device.
                          */
                         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;
+
+                                if (!(qc->tf.flags & ATA_TFLAG_WRITE)) {
+                                        ata_pio_sectors(qc);
+                                        ata_altstatus(ap);
+                                        status = ata_wait_idle(ap);
+                                }
+
+                                /* ata_pio_sectors() might change the
+                                 * state to HSM_ST_LAST. so, the state
+                                 * is changed after ata_pio_sectors().
+                                 */
+                                ap->hsm_task_state = HSM_ST_ERR;
+                                goto fsm_start;
                         }
 
                         ata_pio_sectors(qc);