Re: [linux-usb-devel] Serial-Core: USB-Serial port current issues.

[Paul Fulghum]

Luiz Fernando N. Capitulino wrote:
> |   take mutex
> |   take port lock
> | again:
> |   save local copy of icount
> |   release port lock
> |   get_mctrl
> |   take port lock
> |   if (icount changed)
> |     goto again
> |   update tty->hw_stopped
> |   release port lock
> |   release mutex
>
>  Well, I think it'd work. But how can we keep track of 'icount'?
> Should the driver add 1 if it updates 'tty->hw_stopped'?

The only thing about icount that needs to be
tracked is that it changes, which indicates
an interrupt might have changed hw_stopped.
If icount changes at all, invalidate the last
reading of the state and do it again. The way
icount is incremented is not changed.

Like I said, it is really ugly. I was just looking
for a way of allowing get_mctrl to sleep if necessary.

--
Paul Fulghum
Microgate Systems, Ltd.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/