> From: BLACKSON Jim [mailto:[EMAIL PROTECTED]] ... > Maybe BBB 2.0 should always terminate ... with a > short/null packet.
That's been proposed ... by Me ... as a way of bringing command queueing to usb storage. Such is the state of the usb-mass archives that I can't point you to it. But I remember sharing an epiphany one day, to little response, that maybe the quickest way to explain bInterfaceProtocol x50 was to begin by pretending we actually had ended all Command Out, Data In/Out, and Status In with short/zero packets ... ... this being the one, true, "natural", never specified, way of speaking Scsi over Usb ... ... except then you must also remember that the de facto Microsoft Windows 95B redefinition of Usb forbade ZLP's (zero length packets) Out from the host. This approach boiled all of BBB chapter 6 down to one page. Pat LaVarre P.S. I hear the no ZLP Out reality distorted Usb modem protocols too. -----Original Message----- From: BLACKSON Jim [mailto:[EMAIL PROTECTED]] Sent: Thu 12/12/2002 1:09 AM To: USB Developers; 'Matthew Dharm'; Pat LaVarre Cc: Greg KH; David Brownell; USB Storage List Subject: RE: [usb-storage] Re: [linux-usb-devel] Re: PATCH: usb-storage: make internal structs more consistent Matthew Dharm wrote: > Oh... excellent observation, Pat. A dropped packet would produce almost > exactly this sort of thing... Yes. (But in this case the (extra 13 bytes) CSW ended up in the users buffer, which isn't supposed to happen in BBB Bulk-only Prot=50. :-) I wonder if the dropped packet was lost on the wire, or perhaps due to wrong data toggle (so first packet was dropped). You know, that 13-byte short packet at the end of the bulk data stream worked pretty well to terminate the data transfer. Maybe BBB 2.0 should always terminate the data phase with a short/null packet. Makes for a nice marker on the wire. Then every phase of BBB: command, data, status terminates with a short packet. Might be able to eliminate some stalls that way. :-) Best regards, jimb. Jim Blackson ------------------------------------------------------- This sf.net email is sponsored by: With Great Power, Comes Great Responsibility Learn to use your power at OSDN's High Performance Computing Channel http://hpc.devchannel.org/ _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
