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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 /drivers/scsi/scsi_scan.c
parentf4f4e47e4af6b02dd1c425b931c65d0165356e33 (diff)
downloadlinux-5cd3bbfad088f86bde3e0f038ff4dd5bb0ac5290.tar.bz2
[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>
Diffstat (limited to 'drivers/scsi/scsi_scan.c')
-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 6963d529e0f0..18486b51668d 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;
}