Re: [PATCH] Try #2: Use SCSI read/write(16) with 2TB drives

2012-11-14 Thread Sebastian Andrzej Siewior 
On Wed, Nov 14, 2012 at 12:55:13AM -0500, Jason J. Herne wrote:
 --- 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  0x) {
 + } 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  0x);

The comment is pointless if you assume the reading is able to read C. What
would help is a link either here or in patch's description to the mail thread
where it has been descovered that some 2TB devices don't recognize the small
command.

 +
   /* Rescale capacity to 512-byte units */
   if (sector_size == 4096)
   sdkp-capacity = 3;

Sebastian
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Re: [PATCH] Try #2: Use SCSI read/write(16) with 2TB drives

2012-11-14 Thread Jason J. Herne 
On Wed, Nov 14, 2012 at 2:02 PM, Sebastian Andrzej Siewior
sebast...@breakpoint.cc wrote:
 On Wed, Nov 14, 2012 at 12:55:13AM -0500, Jason J. Herne wrote:
   }
   }

 + /* Use read/write(16) for  2TB disks */
 + sdp-use_16_for_rw = (sdkp-capacity  0x);

 The comment is pointless if you assume the reading is able to read C. What
 would help is a link either here or in patch's description to the mail thread
 where it has been descovered that some 2TB devices don't recognize the small
 command.

I've removed the comment entirely and added a link to the original
post within the patch
description. Resending in separate e-mail.

--
- Jason J. Herne (hern...@gmail.com)
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[PATCH] Try #2: Use SCSI read/write(16) with 2TB drives

2012-11-13 Thread Jason J. Herne 
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  0x) {
+   } 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  0x);
+
/* 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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