diff options
author | Jeff Garzik <jgarzik@pobox.com> | 2005-08-29 15:59:42 -0400 |
---|---|---|
committer | Jeff Garzik <jgarzik@pobox.com> | 2005-08-29 15:59:42 -0400 |
commit | 70d374ea9907036e15574a5ce89219edd5baee10 (patch) | |
tree | b858bb4a841eb91b1d91b41c33698d05fa7bfb37 /drivers/scsi/sata_svw.c | |
parent | aa7e16d6b88b3b38db0d2ee49ed5e44e7b2045ec (diff) | |
parent | bf4e70e54cf31dcca48d279c7f7e71328eebe749 (diff) |
Merge /spare/repo/linux-2.6/
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 3884a3cce75c..19d3bb3b0fb6 100644 --- a/drivers/scsi/sata_svw.c +++ b/drivers/scsi/sata_svw.c | |||
@@ -200,18 +200,18 @@ static void k2_bmdma_start_mmio (struct ata_queued_cmd *qc) | |||
200 | /* start host DMA transaction */ | 200 | /* start host DMA transaction */ |
201 | dmactl = readb(mmio + ATA_DMA_CMD); | 201 | dmactl = readb(mmio + ATA_DMA_CMD); |
202 | writeb(dmactl | ATA_DMA_START, mmio + ATA_DMA_CMD); | 202 | writeb(dmactl | ATA_DMA_START, mmio + ATA_DMA_CMD); |
203 | /* There is a race condition in certain SATA controllers that can | 203 | /* There is a race condition in certain SATA controllers that can |
204 | be seen when the r/w command is given to the controller before the | 204 | be seen when the r/w command is given to the controller before the |
205 | host DMA is started. On a Read command, the controller would initiate | 205 | host DMA is started. On a Read command, the controller would initiate |
206 | the command to the drive even before it sees the DMA start. When there | 206 | the command to the drive even before it sees the DMA start. When there |
207 | are very fast drives connected to the controller, or when the data request | 207 | are very fast drives connected to the controller, or when the data request |
208 | hits in the drive cache, there is the possibility that the drive returns a part | 208 | hits in the drive cache, there is the possibility that the drive returns a part |
209 | or all of the requested data to the controller before the DMA start is issued. | 209 | or all of the requested data to the controller before the DMA start is issued. |
210 | In this case, the controller would become confused as to what to do with the data. | 210 | In this case, the controller would become confused as to what to do with the data. |
211 | In the worst case when all the data is returned back to the controller, the | 211 | In the worst case when all the data is returned back to the controller, the |
212 | controller could hang. In other cases it could return partial data returning | 212 | controller could hang. In other cases it could return partial data returning |
213 | in data corruption. This problem has been seen in PPC systems and can also appear | 213 | in data corruption. This problem has been seen in PPC systems and can also appear |
214 | on an system with very fast disks, where the SATA controller is sitting behind a | 214 | on an system with very fast disks, where the SATA controller is sitting behind a |
215 | number of bridges, and hence there is significant latency between the r/w command | 215 | number of bridges, and hence there is significant latency between the r/w command |
216 | and the start command. */ | 216 | and the start command. */ |
217 | /* issue r/w command if the access is to ATA*/ | 217 | /* issue r/w command if the access is to ATA*/ |
@@ -219,7 +219,7 @@ static void k2_bmdma_start_mmio (struct ata_queued_cmd *qc) | |||
219 | ap->ops->exec_command(ap, &qc->tf); | 219 | ap->ops->exec_command(ap, &qc->tf); |
220 | } | 220 | } |
221 | 221 | ||
222 | 222 | ||
223 | static u8 k2_stat_check_status(struct ata_port *ap) | 223 | static u8 k2_stat_check_status(struct ata_port *ap) |
224 | { | 224 | { |
225 | return readl((void *) ap->ioaddr.status_addr); | 225 | return readl((void *) ap->ioaddr.status_addr); |