On Thu, 2009-10-15 at 13:57 -0500, Scott Wood wrote: > I'd say the dropping approach is quite undesirable (significant > potential for output loss unless the buffer is huge), unless there's > simply no way to safely spin. Hopefully there are no such backends, but > if there are perhaps we can have them return some special code to > indicate that.
Should never spin. Best is to keep a copy in the upper layer of the pending data and throttle (not accept further data from tty layer) until we have managed to flush out that "pending" buffer. > > If we just busy loop, it actually does not matter how we let hvc_console > > react > > on 0, as long as we adopt all backends to use that interface consistent. > > > > On the other hand, backends might want to do special magic on congestion so > > I > > personally tend to let the backend loop instead of hvc_console. But I am > > really > > not sure. > > Doing it in the backend requires the backend to know whether it's being > called for printk or for user I/O. In the latter case, we don't want to > spin, but rather wait for an IRQ (or poll with a timer if there's no IRQ). Ben. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
