[PATCH] use msleep() for RTAS delays

[Paul Mackerras]

Benjamin Herrenschmidt writes:

> We could either do something like
> 
> for (;;) {
> 	rc = rtas_call(...);
> 	if (!rtas_check_busy(rc))
> 		break;

rtas_check_busy might need some state, such as the number of times we
have seen an RTAS_BUSY return value.

> Or something inside rtas_call
> 
> rtas_call_waitbusy(...);

That's a good idea...

Paul.