Has anyone tried using the Palm USB driver on the PC? We are trying to
communicate with PalmOS devices WHILE THEY ARE CONNECTED using USB. Does
anyone have any sample code that does this that we could look at? Is the
code for the PC side of USB hotsync available?
- the Palm USB driver is apparently not reentrant. Win2K
blue-screen crashes occur if you try to write from one
thread while you're reading from a different thread.
Had to work around this problem by reading
and writing from the same thread, although this reduces
performance. Is there any other way around this problem?
Is there a better Palm USB driver?
- Performance under Win2K is lousy -- many packets from the Palm are
lost. Packet loss seems to occur because the Palm USB driver's
read call times out after having put some data in our buffer,
but then reports 0 bytes read instead of the actual number of
bytes read. The data it started to return never appears
again. Increasing the timeout helps marginally, but since
the reading thread must alternate between reading and writing,
increasing the read timeout increases the write latency --
e.g., if you have a 1-sec timeout, outgoing writes must
wait for an average of 0.5 sec before being sent.
Current timeout is 100 msec.
- this bad Win2K performance was seen on a number of
different machines, with two versions of
Hotsync (4.0 and 4.0.2).
- Performance under WinXP and Windows 98 seems fine --
no packet loss observed.
Is there a way to get decent performance under Windows 2000?
- the Palm USB driver generates a ton of bogus reads while the Palm is
shutting down, before we get notified that the USB device has gone
away. Is there any way around this?
Thanks for your help!
Brad A. Myers
Human Computer Interaction Institute
School of Computer Science
Carnegie Mellon University
5000 Forbes Avenue
Pittsburgh, PA 15213-3891
(412) 268-5150
FAX: (412) 268-1266
[EMAIL PROTECTED]
http://www.cs.cmu.edu/~bam
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