Re: strange umass/scsi behaviour

On Wed, 30 Jul 2003, John Hay wrote:
> Does anyone have an idea why the umass/scsi code behave differently
> between if you boot with a device already plugged in as opposed to
> plugging it in later? In my case it is a Sandisk Cruiser. If I plug
> it in before booting, it works just great, but if I plug it in later,
> it does not want to work.
>
> umass0: SanDisk Cruzer, rev 1.10/1.00, addr 2
> da0 at umass-sim0 bus 0 target 0 lun 0
> da0: <SanDisk Cruzer 2.00> Removable Direct Access SCSI-0 device
> da0: 1.000MB/s transfers
> da0: Attempt to query device size failed: NOT READY, Medium not present
> (da0:umass-sim0:0:0:0): READ CAPACITY. CDB: 25 0 0 0 0 0 0 0 0 0
> (da0:umass-sim0:0:0:0): CAM Status: SCSI Status Error
> (da0:umass-sim0:0:0:0): SCSI Status: Check Condition
> (da0:umass-sim0:0:0:0): NOT READY asc:3a,0
> (da0:umass-sim0:0:0:0): Medium not present
> (da0:umass-sim0:0:0:0): Unretryable error
> Opened disk da0 -> 6
> (da0:umass-sim0:0:0:0): READ CAPACITY. CDB: 25 0 0 0 0 0 0 0 0 0
> (da0:umass-sim0:0:0:0): CAM Status: SCSI Status Error
> (da0:umass-sim0:0:0:0): SCSI Status: Check Condition
> (da0:umass-sim0:0:0:0): UNIT ATTENTION asc:28,0
> (da0:umass-sim0:0:0:0): Not ready to ready change, medium may have changed
> (da0:umass-sim0:0:0:0): Retrying Command (per Sense Data)

There's nothing sinister going on here.  What happens is your device is
slow to power up and initialize when plugged in.  It's not ready for the
bus scan from CAM but it's awake enough to answer the initial INQUIRY.
When you boot with it attached, there's a longer delay between when the
port is powered up and CAM scans the device and so you don't get any
messages.

What behavior does the device give after you get the above dmesg?  Does it
print out errors on console that the retry failed? (see last line of the
dmesg).  I've been thinking about adding a bit of a delay to the umass CAM
attach call for such devices.

> uhci0: <Intel 82371AB/EB (PIIX4) USB controller> port 0xece0-0xecff irq 11 at device 7.2 on pci0
> usb0: <Intel 82371AB/EB (PIIX4) USB controller> on uhci0
> usb0: USB revision 1.0
> uhub0: Intel UHCI root hub, class 9/0, rev 1.00/1.00, addr 1
> uhub0: 2 ports with 2 removable, self powered
> umass0: SanDisk Cruzer, rev 1.10/1.00, addr 2

Port powered up.
[~3 secs, perhaps]

> ad0: 6194MB <IBM-DADA-26480> [13424/15/63] at ata0-master UDMA33
> acd0: CDROM <TEAC CD-ROM CD-224E> at ata1-master PIO4
> da0 at umass-sim0 bus 0 target 0 lun 0
> da0: <SanDisk Cruzer 2.00> Removable Direct Access SCSI-0 device
> da0: 1.000MB/s transfers
> da0: 14MB (29120 512 byte sectors: 64H 32S/T 14C)

Device probed.

-Nate