On Wed, 12 Jul 2006, Ajay Jain wrote: > Hi, > > The windows host enumerates my proprieatry device (running linux & my > driver) in the following sequence: > > 1. Reset > 2. Get Dev Desc 64 bytes > 3. Reset > 4. Set Address > 5. Get Dev Desc 18 bytes > 6. Get Config Desc 9 bytes > 7. Get Config Desc 0xff bytes > 8. Get Device Qualifier Desc > 9. Get Dev Desc 18 bytes > 10. Get Config Desc 0x109 bytes > 11. Set config > > I have a few questions here: > > i) When it gets to know the length of config desc in step 6 (=37 in my > case), then why does it ask for 0xff bytes in step 7.
If you wonder why Windows behaves in strange unexplained ways, you're asking on the wrong mailing list. :-) > ii) Why are steps 9 & 10 repeated? Ditto. Try asking someone in Redmond. > iii) Again, in step 10, why does it ask for 0x109 bytes, when it > already knows the whole length from step 6. Where does it get the > magic numbers "0xff" & "0x109" from? Is it possible that you misread something, and those requests are actually for string descriptors rather than config descriptors? In my tests, when asking for a config descriptor Windows always requests either 9 bytes or the correct total length. When asking for a string descriptor, Windows often -- but not always! -- requests 255 bytes (the maximum). > The sequence is always-always the same. The sequence is likely to be different if you look at different versions of Windows. Alan Stern ------------------------------------------------------------------------- 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 _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
