DragonFly kernel List (threaded) for 2008-04
Re: ugen(4) and poll(2)
Hasso Tepper wrote:
As far as I can see what happens is that daemon opens ugen(4) device
correctly and starts to poll(2) interrupt endpoint of the device (devices
have single interface). The trouble is that poll(2) seems to ignore
timeout. It doesn't return until there is data available in the
descriptor. Ie I can make poll(2) to return with poking device, but till
then it blocks.
Before I dig deep into areas I'm not familiar with ... Any ideas why and
where it might happen? Anyone seen something like this?
In which waitchan is the process? If it is in "poll" and you're really
passing a proper timeout value, then everything should work as advertised.
Does a ktrace show only the poll and no return? Sometimes processes
tend to re-call poll over and over again (maybe due to an interrupting
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