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Commit 4451e472 authored by Alan Stern's avatar Alan Stern Committed by James Bottomley
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[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: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
parent e47373ec

drivers/scsi/sd.c

+19 −5
Original line number Diff line number Diff line
@@ -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;

			}

			/* 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))