Brian Buhrow <buhrow%nfbcal.org@localhost> writes: > hello. In looking further at the ugen(4) driver, it looks like there > has been some effort to get things like select/poll(2) working with ugen(4) > connected devices, as well as having read calls return after a specific > timeout interval. Under 5.2, at least, and I think -current as well, I > don't think that machinery is working quite right. Here are the things I > notice as I look at the code. Keep in mind that I'm not an expert with the > way usb works, so there may be huge gaps in my understanding in terms of > what's actually broken. I would suggest that you read the USB specs to really understand how reads work. (I am fuzzy on this at the moment.) Also I would read the linux drivers to see what they do. In order to fix this, I think it's going to be necessary to really understand the details. I find the notion of the driver doing reads on the bus when no program has asked to read a bit odd, but perhaps selecting for read should trigger that since it's like a read.
Attachment:
pgpMY6uyMFtJV.pgp
Description: PGP signature