USB, select/poll for ucom

Danny Braniss danny at
Fri Jun 27 07:58:10 PDT 2003

> I thought that ucom does do that.  It uses ttypoll as its polling
> function, and seems to insert data into the tty structure on an
> interrupt basis.  That is hidden a little bit by the usb driver
> structure.  In the middle of ucomopen we call ucomstartread which
> posts a read onto the bulk in pipe.  This read fires a callback when
> it is 'finished' which the processes the data.  So I think that maybe
> that transfer is never completing.
> Warner

some more reading, and it seems that indeed open fires up a startread,
so that select should work. In my case, i just went the old fashion way,
sigalarm/read,  but it seems that nothing is being read by the driver :-(
assuming that uco/ulpcom works - the problem must be in the way this
smartcard reader works. 


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