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List:       linux-usb
Subject:    Re: [linux-usb] Progress! (was: Prolific ATAPI-USB Bridge)
From:       Doug Alcorn <doug () lathi ! net>
Date:       1999-10-31 2:52:51
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Johannes Erdfelt <jerdfelt@sventech.com> writes:

> On Sat, Oct 30, 1999, Doug Alcorn <doug@lathi.net> wrote:
> > 
> > Doug Alcorn <doug@lathi.net> writes:
> > 
> > > I:  If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=ff Prot=ff Driver=(none)
> > > E:  Ad=01(O) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
> > > E:  Ad=82(I) Atr=02(Bulk) MxPS=  64 Ivl=  0ms
> > > E:  Ad=83(I) Atr=03(Int.) MxPS=   7 Ivl=  1ms
> > 
> > This Cls and Sub led me to believe that the drive is bad.  I found a
> > MS-Windows maching to try and install it on.  It wouldn't work there
> > either.  The manufacturer is sending me a new one tomorrow or the next 
> > day.
> 
> That class and subclass are reserved for vendor specific protocol. This
> means it can be anything. I'd be willing to bet that the new drive will
> have the same class/subclass.
> 

You are probably right.  It's silly to argue about it at this point
(since I will get the new one soon), but the reason I think returning
ff is wrong is that the drive was never fully recognized under
MS-Windows.  It would hang when trying to detect it.  I realize I left 
that info out of my previous message.

I am really hoping that the new drive returns "08" as the class type.
That is how (I think) the usb-scsi module recognizes that it as a mass 
storage device.  If the "ff" is correct, then it will take some custom 
code (I think) at device detection time to load the correct driver.  I 
would guess something like this in usb_scsi.c::scsi_probe() right near 
the top where other exceptions are handled:

	if (dev->descriptor.idVendor == 0x067b
	    && !strcmp(dev->descriptor.idProduct, "2307")
	    && dev->descriptor.bDeviceClass == 0xff) {
		/* don't know if the class would have to be reset or not */
		dev->descriptor.bDeviceClass  = USB_CLASS_MASS_STORAGE;
		subclass = US_SC_SCSI;
		protocol = US_PR_CBI;
	}

-- 
 (__)  Doug Alcorn           
 oo /  doug@lathi.net 
 |_/   "If you don't have the source, it's not software"

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