[PATCH] libata-dev: ata_check_atapi_dma() fix for ATA_FLAG_PIO_POLLING LLDDs

ata_check_atapi_dma() fix for LLDDs with the ATA_FLAG_PIO_POLLING flag.

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

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index ef0d0dd90e17..61c120dae74d 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2883,6 +2883,15 @@ int ata_check_atapi_dma(struct ata_queued_cmd *qc)
         if (ap->ops->check_atapi_dma)
                 rc = ap->ops->check_atapi_dma(qc);
 
+        /* We don't support polling DMA.
+         * Use PIO if the LLDD handles only interrupts in
+         * the HSM_ST_LAST state and the ATAPI device
+         * generates CDB interrupts.
+         */
+        if ((ap->flags & ATA_FLAG_PIO_POLLING) &&
+            (qc->dev->flags & ATA_DFLAG_CDB_INTR))
+                rc = 1;
+
         return rc;
 }
 /**
@@ -4038,6 +4047,7 @@ unsigned int ata_qc_issue_prot(struct ata_queued_cmd *qc)
                         break;
                 case ATA_PROT_ATAPI_DMA:
                         if (qc->dev->flags & ATA_DFLAG_CDB_INTR)
+                                /* see ata_check_atapi_dma() */
                                 BUG();
                         break;
                 default: