On Mon, Aug 01, 2005 at 10:04:25PM +0300, victor cruceru wrote: > In conclusion: > any difference between open with O_NONBLOCK and open without it for this > kind of devices? > Because man 2 open says: > ---------------------------------------------------------------------------------------------------- > If the O_NONBLOCK flag is specified and the open() system call would result > in > the process being blocked for some reason (e.g., waiting for carrier on a > dialup line), open() returns immediately. The descriptor remains in non- > blocking mode for subsequent operations. > ----------------------------------------------------------------------------------------------------
Then make it always fail for disk devices. I really don't know what you expect to win with this. There is no other choice. There are many short time blocks you won't noice, e.g. openeing a device requiring GIANT or any other lock. You can't open any kind device without a risk to block for a very short time. But still you are talking about a broken device - replace or fix it and return to real problems. Really - a disk should know if it is ready or not and I won't call it blocking if you ask a disk about it. If you want a workaround then fork another process opening the device for you and passing the descriptor back to you via domain socket. > On 8/1/05, Bernd Walter <[EMAIL PROTECTED]> wrote: > > > > On Mon, Aug 01, 2005 at 09:41:30PM +0300, victor cruceru wrote: > > > Well, if you are doing this from a daemon (multiplexing a lot of events) > > > which is blocked in this open syscall, even 1 second is not reasonable. > > In > > > my case it is something more than 30 of seconds (again, on a 5.4 box). > > I'll > > > give it a try on FreeBSD 6. I'm currently investigating if there is > > > something like TEST_UNIT_READY (for both ATAPI and SCSI) which can be > > issued > > > on a control device (i.e. /dev/ata) > > > > What do you expect it to do? > > Ask the device about the state or always fail, because it is not > > allowed to ask the device? > > In your case you have a broken device, this isn't much of an argument. > > A resonable reply time for a USB device would be less then 10ms. -- B.Walter BWCT http://www.bwct.de [EMAIL PROTECTED] [EMAIL PROTECTED] _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
