On 7/10/06, Alan Stern <[EMAIL PROTECTED]> wrote: > On Mon, 10 Jul 2006, Ajay Jain wrote: > > > Hi, > > Am using a windows host and a proprietary device as a function. This > > is the pre-enumeration stage that I am talking about. I see a very > > different behavior with what is written in the standard or with the > > way windows is supposed to enumerate. The following are the > > observations with CATC protocol analyzer. As I understand, there > > should be a reset followed by a get dev descriptor request and then a > > reset again which will be followed by set address and then no more > > resets for the duration of enumeration. Here I am seeing 4 superfluous > > resets and suspends in the beginning. Is it any windows oddity? > > No, it is a device oddity. > > Remember the definitions of reset and suspend. Reset is an SE0 signal, > which is the default bus state when no device is attached or the device's > pull-up resistor hasn't been turned on. Suspend is a J signal, which is > the default bus state when the device's pull-up resistor is on and the > port is disabled. > > So when you see the bus go between reset and suspend, it means that the > device is turning its pull-up resistor off and on.
May be yes, but then I have a counter observation. When I use another host I always see a reset - suspend - reset - get_device_descriptor - reset - set_address sequence. This is something that I observe invariably. When I use the old host, I always see reset - suspend - reset - suspend - reset - suspend - reset - suspend - reset - get_device_descriptor - reset - set_address sequence. The observations on both these pc's is invariable. If it was a device oddity, then why would it behave differently on two different hosts? > Or maybe it means the device's data pins are intermittently making and > breaking contact with the cable's pins. Not my case, because my the cable is connected to the pc since the hardware boots up. There is an ample time (>20s) for booting etc. to complete and usb to get loaded. > It has nothing to do with the host. Ajay ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
