libata: automatically use DMADIR if drive/bridge requires it

Back in 2.6.17-rc2, a libata module parameter was added for atapi_dmadir.

That's nice, but most SATA devices which need it will tell us about it
in their IDENTIFY PACKET response, as bit-15 of word-62 of the
returned data (as per ATA7, ATA8 specifications).

So for those which specify it, we should automatically use the DMADIR bit.
Otherwise, disc writing will fail by default on many SATA-ATAPI drives.

This patch adds ATA_DFLAG_DMADIR and make ata_dev_configure() set it
if atapi_dmadir is set or identify data indicates DMADIR is necessary.
atapi_xlat() is converted to check ATA_DFLAG_DMADIR before setting
DMADIR.

Original patch is from Mark Lord.

Signed-off-by: Tejun Heo <[email protected]>
Cc: Mark Lord <[email protected]>
Signed-off-by: Jeff Garzik <[email protected]>
This commit is contained in:
Tejun Heo 2008-02-21 13:25:50 +09:00 • committed by Jeff Garzik
commit 9116300634
4 changed files with 17 additions and 3 deletions

View file

@ -2396,6 +2396,7 @@ int ata_dev_configure(struct ata_device *dev)
else if (dev->class == ATA_DEV_ATAPI) {
const char *cdb_intr_string = "";
const char *atapi_an_string = "";
const char *dma_dir_string = "";
u32 sntf;
rc = atapi_cdb_len(id);
@ -2436,13 +2437,19 @@ int ata_dev_configure(struct ata_device *dev)
cdb_intr_string = ", CDB intr";
}
if (atapi_dmadir || atapi_id_dmadir(dev->id)) {
dev->flags |= ATA_DFLAG_DMADIR;
dma_dir_string = ", DMADIR";
}
/* print device info to dmesg */
if (ata_msg_drv(ap) && print_info)
ata_dev_printk(dev, KERN_INFO,
"ATAPI: %s, %s, max %s%s%s\n",
"ATAPI: %s, %s, max %s%s%s%s\n",
modelbuf, fwrevbuf,
ata_mode_string(xfer_mask),
cdb_intr_string, atapi_an_string);
cdb_intr_string, atapi_an_string,
dma_dir_string);
}
/* determine max_sectors */

View file

@ -2582,7 +2582,8 @@ static unsigned int atapi_xlat(struct ata_queued_cmd *qc)
qc->tf.protocol = ATAPI_PROT_DMA;
qc->tf.feature |= ATAPI_PKT_DMA;
if (atapi_dmadir && (scmd->sc_data_direction != DMA_TO_DEVICE))
if ((dev->flags & ATA_DFLAG_DMADIR) &&
(scmd->sc_data_direction != DMA_TO_DEVICE))
/* some SATA bridges need us to indicate data xfer direction */
qc->tf.feature |= ATAPI_DMADIR;
}