On Mon, 11 Jul 2005, Roberts-Thomson, James wrote:
> OK, it turns out that for this particular key, a two second pause after
> "sd_spinup_disk" is called and before "sd_read_capacity" will make it work.
> The 'dmesg' (or syslog) output is still ugly, however; but once I realised
> that it was "sd_spinup_disk" that:
>
> A) needed the delay, and
> B) causes the first ugly message to be printed in the first place, then a
> better patch came to mind.
>
> So, after combining Alan's suggestion to use "msleep" rather than my
> previous convoluted method, and moving the location of the pause to inside
> sd_spinup_disk (and targeting it to remove the first "ugly"), I came up with
> a better patch, which is attached.
>
> This patch adds the module parameter 'firmware_delay', and will cause a
> pause for "firmware_delay" seconds inside sd_spinup_disk when the first SCSI
> command returns UNIT_ATTENTION as the sense key.
>
> Again, I have deliberately made the default value for this parameter 0,
> which means that the end-user will need to ensure insmod or modprobe
> supplies a >0 value to firmware_delay before the patch takes effect.
>
> I'm not sure what the procedure is for getting this patch officially
> recognised for inclusion into the kernel - Alan, are you able to "sponsor"
> this patch for inclusion?
How about the patch below instead? It's a bit easier to use, in that it
doesn't require users to know about a new parameter. Also it retries at
1-second intervals for up to 5 seconds, which makes it a little more
flexible. If this works for you, I'll submit it for inclusion in the
official kernel.
Alan Stern
Index: usb-2.6/drivers/scsi/sd.c
===================================================================
--- usb-2.6.orig/drivers/scsi/sd.c
+++ usb-2.6/drivers/scsi/sd.c
@@ -987,7 +987,7 @@ 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;
@@ -1074,12 +1074,27 @@ sd_spinup_disk(struct scsi_disk *sdkp, c
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 typical 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 */
@@ -1091,8 +1106,7 @@ sd_spinup_disk(struct scsi_disk *sdkp, c
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))
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