On Tue, Nov 04, 2014 at 01:01:00PM +0000, Mark Knibbs wrote:
>
> This patch does two things for SCM eUSCSI USB-SCSI converters:
>
> 1. SCM eUSCSI bridge devices are hard-wired to use SCSI ID 7. On connecting
> the converter, access to that ID is attempted during the bus scan. Asking
> the converter to issue INQUIRY commands to itself isn't very polite and
> wastes time. Set this_id to 7 so __scsi_scan_target() skips it in the scan.
>
> 2. Enable multi-LUN support. eUSCSI devices don't support Get Max LUN
> requests, returning an error (-32). [Different targets could have different
> numbers of LUNs, so it wouldn't make sense to return a particular value in
> response to Get Max LUN.]
>
> usb_stor_scan_dwork() does this:
> /* For bulk-only devices, determine the max LUN value */
> if (us->protocol == USB_PR_BULK && !(us->fflags & US_FL_SINGLE_LUN)) {
> mutex_lock(&us->dev_mutex);
> us->max_lun = usb_stor_Bulk_max_lun(us);
> mutex_unlock(&us->dev_mutex);
>
> It avoids calling usb_stor_Bulk_max_lun() if US_FL_SINGLE_LUN, but not for
> US_FL_SCM_MULT_TARG. Since usb_stor_Bulk_max_lun() returns 0 in the error
> case, us->max_lun was always set to 0.
>
> [If the user doesn't want multi-LUN support (perhaps there are SCSI devices
> which respond to commands on all LUNs?), the US_FL_SINGLE_LUN quirk can be
> specified on the kernel command line.]
>
>
> Signed-off-by: Mark Knibbs <ma...@clara.co.uk>
>
> ---
> diff -up linux-3.17/drivers/usb/storage/usb.c.orig
> linux-3.17/drivers/usb/storage/usb.c
> --- linux-3.17/drivers/usb/storage/usb.c.orig 2014-10-05 20:23:04.000000000
> +0100
> +++ linux-3.17/drivers/usb/storage/usb.c 2014-10-16 22:11:31.000000000
> +0100
> @@ -877,7 +877,9 @@ static void usb_stor_scan_dwork(struct w
> dev_dbg(dev, "starting scan\n");
>
> /* For bulk-only devices, determine the max LUN value */
> - if (us->protocol == USB_PR_BULK && !(us->fflags & US_FL_SINGLE_LUN)) {
> + if (us->protocol == USB_PR_BULK &&
> + !(us->fflags & US_FL_SINGLE_LUN) &&
> + !(us->fflags & US_FL_SCM_MULT_TARG)) {
> mutex_lock(&us->dev_mutex);
> us->max_lun = usb_stor_Bulk_max_lun(us);
> mutex_unlock(&us->dev_mutex);
> @@ -976,13 +978,24 @@ int usb_stor_probe2(struct us_data *us)
> usb_stor_dbg(us, "Transport: %s\n", us->transport_name);
> usb_stor_dbg(us, "Protocol: %s\n", us->protocol_name);
>
> + if (us->fflags & US_FL_SCM_MULT_TARG) {
> + /*
> + * SCM eUSCSI bridge devices can have different numbers
> + * of LUNs on different targets; allow all to be probed.
> + */
> + us->max_lun = 7;
> + /* The eUSCSI itself has ID 7, so avoid scanning that */
> + us_to_host(us)->this_id = 7;
> + /* max_id is 8 initially, so no need to set it here */
> + } else {
> + /* In the normal case there is only a single target */
> + us_to_host(us)->max_id = 1;
> + }
> +
> /* fix for single-lun devices */
> if (us->fflags & US_FL_SINGLE_LUN)
> us->max_lun = 0;
>
> - if (!(us->fflags & US_FL_SCM_MULT_TARG))
> - us_to_host(us)->max_id = 1;
> -
> /* Find the endpoints and calculate pipe values */
> result = get_pipes(us);
> if (result)
This too doesn't apply, can you please refresh it and resend?
thanks,
greg k-h
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