diff options
Diffstat (limited to 'drivers/scsi/sata_svw.c')
| -rw-r--r-- | drivers/scsi/sata_svw.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/drivers/scsi/sata_svw.c b/drivers/scsi/sata_svw.c index 858e07185db..6fd2ce1ffcd 100644 --- a/drivers/scsi/sata_svw.c +++ b/drivers/scsi/sata_svw.c @@ -195,18 +195,18 @@ static void k2_bmdma_start_mmio (struct ata_queued_cmd *qc) /* start host DMA transaction */ dmactl = readb(mmio + ATA_DMA_CMD); writeb(dmactl | ATA_DMA_START, mmio + ATA_DMA_CMD); - /* There is a race condition in certain SATA controllers that can - be seen when the r/w command is given to the controller before the + /* There is a race condition in certain SATA controllers that can + be seen when the r/w command is given to the controller before the host DMA is started. On a Read command, the controller would initiate the command to the drive even before it sees the DMA start. When there - are very fast drives connected to the controller, or when the data request + are very fast drives connected to the controller, or when the data request hits in the drive cache, there is the possibility that the drive returns a part or all of the requested data to the controller before the DMA start is issued. In this case, the controller would become confused as to what to do with the data. In the worst case when all the data is returned back to the controller, the controller could hang. In other cases it could return partial data returning in data corruption. This problem has been seen in PPC systems and can also appear - on an system with very fast disks, where the SATA controller is sitting behind a + on an system with very fast disks, where the SATA controller is sitting behind a number of bridges, and hence there is significant latency between the r/w command and the start command. */ /* issue r/w command if the access is to ATA*/ @@ -214,7 +214,7 @@ static void k2_bmdma_start_mmio (struct ata_queued_cmd *qc) ap->ops->exec_command(ap, &qc->tf); } - + static u8 k2_stat_check_status(struct ata_port *ap) { return readl((void *) ap->ioaddr.status_addr); |