[SCSI] sd: pause in sd_spinup_disk for slow USB devices
This patch adds a delay tailored for USB flash devices that are slow to
initialize their firmware. The symptom is a repeated Unit Attention with
ASC=0x28 (Not Ready to Ready transition). The patch will wait for up to 5
seconds for such devices to become ready. Normal devices won't send the
repeated Unit Attention sense key and hence won't trigger the patch.
This fixes a problem with James Roberts-Thomson's USB device, and I've
seen several reports of other devices exhibiting the same symptoms --
presumably they will be helped as well.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 0410e1b..41ba080 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -984,7 +984,7 @@
sd_spinup_disk(struct scsi_disk *sdkp, char *diskname,
struct scsi_request *SRpnt, unsigned char *buffer) {
unsigned char cmd[10];
- unsigned long spintime_value = 0;
+ unsigned long spintime_expire = 0;
int retries, spintime;
unsigned int the_result;
struct scsi_sense_hdr sshdr;
@@ -1071,12 +1071,27 @@
scsi_wait_req(SRpnt, (void *)cmd,
(void *) buffer, 0/*512*/,
SD_TIMEOUT, SD_MAX_RETRIES);
- spintime_value = jiffies;
+ spintime_expire = jiffies + 100 * HZ;
+ spintime = 1;
}
- spintime = 1;
/* Wait 1 second for next try */
msleep(1000);
printk(".");
+
+ /*
+ * Wait for USB flash devices with slow firmware.
+ * Yes, this sense key/ASC combination shouldn't
+ * occur here. It's characteristic of these devices.
+ */
+ } else if (sense_valid &&
+ sshdr.sense_key == UNIT_ATTENTION &&
+ sshdr.asc == 0x28) {
+ if (!spintime) {
+ spintime_expire = jiffies + 5 * HZ;
+ spintime = 1;
+ }
+ /* Wait 1 second for next try */
+ msleep(1000);
} else {
/* we don't understand the sense code, so it's
* probably pointless to loop */
@@ -1088,8 +1103,7 @@
break;
}
- } while (spintime &&
- time_after(spintime_value + 100 * HZ, jiffies));
+ } while (spintime && time_before_eq(jiffies, spintime_expire));
if (spintime) {
if (scsi_status_is_good(the_result))