On Fri, Jun 02, 2006 at 03:41:21PM -0700, Pete Zaitcev wrote:
> On Fri, 2 Jun 2006 13:50:14 -0700, Greg KH <[email protected]> wrote:
> > On Fri, Jun 02, 2006 at 12:03:14AM -0300, Luiz Fernando N.Capitulino wrote:
> > > 2. The new pl2303's set_termios() can (still) sleep. Serial Core's
> > > documentation says that that method must not sleep, but I couldn't find
> > > where in the Serial Core code it's called in atomic context. So, is this
> > > still true? Isn't the Serial Core's documentation out of date?
> > If this is true then we should just stop the port right now, as the USB
> > devices can not handle this. They need to be able to sleep to
> > accomplish this functionality.
> > Russell, is this a requirement of the serial layer? Why?
> Shouldn't it be all right to schedule the change at the moment of
> that call and have it happen later? Resisting a temptation to abuse
> keventd and schedule_work and using a tasklet may help with latency
> enough to make this tolerable.
Some devices require more than one usb message to set all of the proper
termios bits in the device. Creating a way to queue them up and fire
them off later, and handle errors if something happened in the middle,
after we told userspace the termios change succeeded, might get quite
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