From: "Jason J. Herne" <hern...@gmail.com>
Force large capacity (> 2TB) drives to use READ/WRITE(16) instead of
READ/WRITE(10). Some(most/all?) USB enclosures do not like READ(10) commands
when a large capacity drive is installed.
Signed-off-by: Jason J. Herne <hern...@gmail.com>
---
drivers/scsi/sd.c | 5 ++++-
include/scsi/scsi_device.h | 1 +
2 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 12f6fdf..9611d6b 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -887,7 +887,7 @@ static int sd_prep_fn(struct request_queue *q, struct
request *rq)
SCpnt->cmnd[29] = (unsigned char) (this_count >> 16) & 0xff;
SCpnt->cmnd[30] = (unsigned char) (this_count >> 8) & 0xff;
SCpnt->cmnd[31] = (unsigned char) this_count & 0xff;
- } else if (block > 0xffffffff) {
+ } else if (sdp->use_16_for_rw) {
SCpnt->cmnd[0] += READ_16 - READ_6;
SCpnt->cmnd[1] = protect | ((rq->cmd_flags & REQ_FUA) ? 0x8 :
0);
SCpnt->cmnd[2] = sizeof(block) > 4 ? (unsigned char) (block >>
56) & 0xff : 0;
@@ -2054,6 +2054,9 @@ got_data:
}
}
+ /* Use read/write(16) for > 2TB disks */
+ sdp->use_16_for_rw = (sdkp->capacity > 0xffffffff);
+
/* Rescale capacity to 512-byte units */
if (sector_size == 4096)
sdkp->capacity <<= 3;
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 88fae8d..19ab8f1 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -135,6 +135,7 @@ struct scsi_device {
* because we did a bus reset. */
unsigned use_10_for_rw:1; /* first try 10-byte read / write */
unsigned use_10_for_ms:1; /* first try 10-byte mode sense/select */
+ unsigned use_16_for_rw:1; /* Use read/write(16) over read/write(10) */
unsigned skip_ms_page_8:1; /* do not use MODE SENSE page 0x08 */
unsigned skip_ms_page_3f:1; /* do not use MODE SENSE page 0x3f */
unsigned skip_vpd_pages:1; /* do not read VPD pages */
--
1.7.9.5
--
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