Oh... excellent observation, Pat. A dropped packet would produce almost exactly this sort of thing...
Matt On Tue, Dec 10, 2002 at 02:54:26PM -0700, Pat LaVarre wrote: > > the device reports: > > I: If#= 0 Alt= 0 #EPs= 3 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage > > Thanks for quoting this. > > > Nope > > Ouch, lost me, sorry. What a reader of the Usb spec > might phrase as "bInterfaceClass = x08" or > "bDeviceClass = x08" here appears as "Cls=08(stor.)". > And "bInterfaceProtocol = x50" here appears as > "Prot=50". Yes? > > So here we do have a context where block data is > commonly a multiple of x200 (512) bytes but CBW & CSW > contain just x1F (31) and x0D (13) bytes each. > > Yes? > > > > When working with perfect devices, a host thinking > > > that CSW In is Data In is a host that dropped a > > > Data In packet. > > > > This is very reproducable on USB 2.0 with only a > > "mount" command. When running as a 1.1 device, it > > works just fine... > > Lost me again, sorry. What reason do we have to > believe that it is the device, not the host, that > starts dropping data packets when we switch to Usb2 HS > from Usb1 FS? > > Maybe it's host hardware, not the host software per > se, that drops packets? > > Yours in breathtaking ignorance, Pat LaVarre > > -----Original Message----- > From: Greg KH [mailto:[EMAIL PROTECTED]] > Sent: Tue 12/10/2002 2:45 PM > To: Pat LaVarre > Cc: David Brownell; USB Developers; USB Storage List > Subject: Re: [usb-storage] Re: [linux-usb-devel] Re: PATCH: usb-storage: make >internal structs more consistent > > > > On Tue, Dec 10, 2002 at 02:40:01PM -0700, Pat LaVarre wrote: > > "13 bytes not 512" is rather suspicious if we have bInterfaceClass > > ...Protocol = x 08 50. In that context, 13 just happens to be the > > length of a CSW. How sure are we that the packet here is data? Do we > > know if its first four bytes are "USBS", as we would expect in a CSW? > > Nope, the device reports: > I: If#= 0 Alt= 0 #EPs= 3 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage > > > When working with perfect devices, a host thinking that CSW In is Data > > In is a host that dropped a Data In packet. > > This is very reproducable on USB 2.0 with only a "mount" command. When > running as a 1.1 device, it works just fine... > > greg k-h > > > _______________________________________________ > usb-storage mailing list > [EMAIL PROTECTED] > http://www2.one-eyed-alien.net/mailman/listinfo/usb-storage -- Matthew Dharm Home: [EMAIL PROTECTED] Maintainer, Linux USB Mass Storage Driver Hi. I have my back hairs caught in my computer fan. -- Customer User Friendly, 8/20/1998
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