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

[deliverable/linux.git] / drivers / scsi / libata-core.c

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index ef0d0dd90e175d2aa9088ca18bfb68bff4638319..61c120dae74d0ce2c4e61717a073fb733ed9c686 100644 (file)
--- 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: