1 files changed, 14 insertions, 4 deletions

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index df2e05738f3b..ea53e6a570b4 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2305,8 +2305,8 @@ static void atapi_request_sense(struct ata_queued_cmd *qc)
                 qc->tf.feature |= ATAPI_PKT_DMA;
         } else {
                 qc->tf.protocol = ATA_PROT_ATAPI;
-                qc->tf.lbam = (8 * 1024) & 0xff;
-                qc->tf.lbah = (8 * 1024) >> 8;
+                qc->tf.lbam = SCSI_SENSE_BUFFERSIZE;
+                qc->tf.lbah = 0;
         }
         qc->nbytes = SCSI_SENSE_BUFFERSIZE;
 
@@ -2415,6 +2415,7 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
         struct ata_device *dev = qc->dev;
         int using_pio = (dev->flags & ATA_DFLAG_PIO);
         int nodata = (scmd->sc_data_direction == DMA_NONE);
+        unsigned int nbytes;
 
         memset(qc->cdb, 0, dev->cdb_len);
         memcpy(qc->cdb, scmd->cmnd, scmd->cmd_len);
@@ -2434,14 +2435,20 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
         if (!using_pio && ata_check_atapi_dma(qc))
                 using_pio = 1;
 
+        /* Some controller variants snoop this value for Packet transfers
+           to do state machine and FIFO management. Thus we want to set it
+           properly, and for DMA where it is effectively meaningless */
+        nbytes = min(qc->nbytes, (unsigned int)63 * 1024);
+
+        qc->tf.lbam = (nbytes & 0xFF);
+        qc->tf.lbah = (nbytes >> 8);
+
         if (using_pio || nodata) {
                 /* no data, or PIO data xfer */
                 if (nodata)
                         qc->tf.protocol = ATA_PROT_ATAPI_NODATA;
                 else
                         qc->tf.protocol = ATA_PROT_ATAPI;
-                qc->tf.lbam = (8 * 1024) & 0xff;
-                qc->tf.lbah = (8 * 1024) >> 8;
         } else {
                 /* DMA data xfer */
                 qc->tf.protocol = ATA_PROT_ATAPI_DMA;
@@ -2452,6 +2459,9 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
                         qc->tf.feature |= ATAPI_DMADIR;
         }
 
+
+        /* FIXME: We need to translate 0x05 READ_BLOCK_LIMITS to a MODE_SENSE
+           as ATAPI tape drives don't get this right otherwise */
         return 0;
 }