Paul Mackerras wrote:

Haren Myneni writes:

quoted

+	WARN_ON(rc == -2 || (rc >= 9900 && rc <= 9905));

This worries me... do we know for sure that RTAS will never return a
busy code?  If it could possibly return a busy code, and we can't
sleep, then we should spin doing the call again and again until it
works, I think.

The PAPR marks certain RTAS calls as "fast", meaning they must not
return any kind of busy status.  Manipulating the GIQ (set-indicator
with token 9005) is defined as "fast".