[PATCH] Regression in 2.6.19-rc microcode driver

If the microcode driver is built in (rather than module) there are some,
ehm, interesting effects happening due to the new "call out to userspace"
behavior that is introduced..  and which runs too early.  The result is a
boot hang; which is really nasty.

The patch below is a minimally safe patch to fix this regression for 2.6.19
by just not requesting actual microcode updates during early boot.  (That
is a good idea in general anyway)

The "real" fix is a lot more complex given the entire cpu hotplug scenario
(during cpu hotplug you normally need to load the microcode as well); but
the interactions for that are just really messy at this point; this fix at
least makes it work and avoids a full detangle of hotplug.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/i386/kernel/microcode.c b/arch/i386/kernel/microcode.c
index c4d0291..23f5984 100644 (file)
--- a/arch/i386/kernel/microcode.c
+++ b/arch/i386/kernel/microcode.c
@@ -577,7 +577,7 @@ static void microcode_init_cpu(int cpu)
        set_cpus_allowed(current, cpumask_of_cpu(cpu));
        mutex_lock(&microcode_mutex);
        collect_cpu_info(cpu);
-       if (uci->valid)
+       if (uci->valid && system_state == SYSTEM_RUNNING)
                cpu_request_microcode(cpu);
        mutex_unlock(&microcode_mutex);
        set_cpus_allowed(current, old);