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authorFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>2008-12-05 11:21:46 +0900
committerJames Bottomley <James.Bottomley@HansenPartnership.com>2008-12-29 11:24:24 -0600
commit5cd3bbfad088f86bde3e0f038ff4dd5bb0ac5290 (patch)
tree090f7dee647162251397a8378a01454390a02bcd
parentf4f4e47e4af6b02dd1c425b931c65d0165356e33 (diff)
[SCSI] retry with missing data for INQUIRY
This patch changes scsi_probe_lun() to retry INQUIRY if the device has not actually sent back any INQUIRY data, This enables the Thecus N2050 storage device to work better. The firmware on that device starts up strangely; it sends no data in response to the initial INQUIRY, and it sends the INQUIRY information in response to the followup REQUEST SENSE. But after that it works better, so retrying the INQUIRY is enough to get it going. Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
-rw-r--r--drivers/scsi/scsi_scan.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 6963d529e0f..18486b51668 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -573,6 +573,8 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
/* Each pass gets up to three chances to ignore Unit Attention */
for (count = 0; count < 3; ++count) {
+ int resid;
+
memset(scsi_cmd, 0, 6);
scsi_cmd[0] = INQUIRY;
scsi_cmd[4] = (unsigned char) try_inquiry_len;
@@ -582,7 +584,7 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
inq_result, try_inquiry_len, &sshdr,
HZ / 2 + HZ * scsi_inq_timeout, 3,
- NULL);
+ &resid);
SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: INQUIRY %s "
"with code 0x%x\n",
@@ -603,6 +605,14 @@ static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
(sshdr.ascq == 0))
continue;
}
+ } else {
+ /*
+ * if nothing was transferred, we try
+ * again. It's a workaround for some USB
+ * devices.
+ */
+ if (resid == try_inquiry_len)
+ continue;
}
break;
}