On Thu, Aug 30, 2007 at 03:33:36PM -0400, Mike Frysinger wrote: > i noticed that while using minicom on a usb-serial device (PL2303), > disconnecting it would make minicom spike using all the cpu. looking into > it, minicom does a simple select()/read() on the fd on the device, but those > functions werent returning errors so it kept on looping. a simple test > program shows similar behavior: open a usb serial device, set the fd to > nonblocking, and then in a loop just keep doing a read(). while the usb > cable is plugged in, you get back the normal EAGAIN. but when you unplug the > device, read() just returns 0 rather than ENODEV or EIO.
You should get a tty hangup sent on the filedescriptor, right? And read returning 0 is just fine, I don't see why that is illegal, as it's the tty layer returning that information. You need to handle the tty hangup event (and so should minicom, which I find hard to believe it doesn't...) What kernel version are you seeing this on? thanks, greg k-h ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Linux-usb-users@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
