Mark Lord wrote:
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.
Signed-off-by: Mark Lord <mlord@xxxxxxxxx>
--- old/drivers/ata/libata-scsi.c 2008-02-18 14:45:08.000000000 -0500
+++ linux/drivers/ata/libata-scsi.c 2008-02-18 14:53:02.000000000 -0500
@@ -2543,9 +2543,10 @@
qc->tf.protocol = ATAPI_PROT_DMA;
qc->tf.feature |= ATAPI_PKT_DMA;
- if (atapi_dmadir && (scmd->sc_data_direction != DMA_TO_DEVICE))
- /* some SATA bridges need us to indicate data xfer
direction */
- qc->tf.feature |= ATAPI_DMADIR;
+ /* some SATA bridges need us to indicate data xfer direction */
+ if (atapi_dmadir || (dev->id[62] & 0x8000))
+ if (scmd->sc_data_direction != DMA_TO_DEVICE)
+ qc->tf.feature |= ATAPI_DMADIR;
Regardless of the historical usage (or lack thereof) of that I.D. word,
I would prefer
1) an ata version check
2) a simple wrapper in linux/ata.h, similar to the many that already exist
So, conditional ACK...
-
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