Re: Patch to fix/shorten "wi" freezes

In message <[email protected]>, "M. Warner Losh" writes:
>
>For the removal, it would be better to use the bus_child_present() api
>for the eject case.

Does the pccard system implement bus_child_present()? I just did a
quick grep for *_child_present there without finding anything, but
maybe I'm looking for the wrong thing. Is the idea to use something
like

	if (sc->wi_gone)
		return;
	<hardware operation>
	if (timeout) {
		if (!bus_child_present(sc->dev)) {
			sc->wi_gone = 1;
			return;
		}
		device_printf(sc->dev, "device timeout\n");
	}

so that further slow timeouts can be avoided if the device has
really been removed? I presume it is too much overhead to just call
bus_child_present() everywhere instead of testing `gone'.

>For the hardware becomes confused case, setting
>gone means that nothing further will happen with the card.  However,
>the other parts of this patch seem relatively reasonable to me.

Yes, this is a problem if some devices report errors and then come
back to life. The problems I have seen don't recover, but I guess
that will not always be the case. In the patch the `gone' flag is
set when status is 0xffff after a timeout and when the "busy bit
won't clear" error occurs. Hopefully these are both usually cases
where the hardware does not recover itself.

Ian



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