[PATCH 16/16] ARM: omap: disable cpuidle for OMAP3 platforms

Kevin Hilman [off-list ref] writes:

Tony Lindgren [off-list ref] writes:

quoted

* Russell King - ARM Linux [off-list ref] [120208 08:10]:

quoted

Commit 2fd149645eb4 (ARM: OMAP2+: UART: Remove omap_uart_can_sleep and add pm_qos)
has caused a regression on OMAP3 platforms.

When the UART is trying to transmit data, if we enter a low power mode,
transmission stops, which makes serial on OMAP3 unusable - a 'dmesg'
takes five minutes to be output at 115200 baud, at a rate of around a
block of 16 characters every couple of seconds.

Unfortunately, the commit above can't be reverted because of many other
changes in this area, so this implements a dirty fix by disabling
CPU idle in the places the original commit does, irrespective of the
UART state.

...

quoted

--- a/arch/arm/mach-omap2/pm34xx.c
+++ b/arch/arm/mach-omap2/pm34xx.c

@@ -421,7 +421,7 @@ static void omap3_pm_idle(void)
 	local_irq_disable();
 	local_fiq_disable();
 
-	if (omap_irq_pending() || need_resched())
+	if (omap_irq_pending() || need_resched() || 1)
 		goto out;
 
 	trace_power_start(POWER_CSTATE, 1, smp_processor_id());

Argh, this is just too ugly. There has got to be a better fix for the
-rc series.

Looks like the patches to fix omap-serial.c are queued for v3.4,
so that won't help.

Kevin, what do you have for the -rc fix here to avoid the if (1)
hack?

There was confusion with Greg about this serial fixes which were
supposed to be for -rc.

He pulled the original series in to -rc, and reverted them when Paul
updated the series.  Then he decided to queue the updated series for
3.4. :(

I've now asked Greg if he can queue that series for 3.3.

And he refused (on the 34xx thread). :(

It is a very targetted set of fixes that directly address the problems
in the UART driver, but he has decided they should wait because we went
through a couple revisions.

Maybe you can respond to Greg saying that we really need them for 3.3?

Kevin