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[SCSI] sd: pause in sd_spinup_disk for slow USB devices

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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>
This commit is contained in:
Alan Stern 2005-07-12 10:45:17 -04:00 committed by James Bottomley
parent e47373ec1c
commit 4451e47262
1 changed files with 19 additions and 5 deletions
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24
drivers/scsi/sd.c
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@ -984,7 +984,7 @@ static void
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 @@ sd_spinup_disk(struct scsi_disk *sdkp, char *diskname,
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 @@ sd_spinup_disk(struct scsi_disk *sdkp, char *diskname,
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))