Subject: Panda ES board hang when using GPIO as interrupt

From: [email-masked] (Franky Lin)
Date: Mon, 25 Jun 2012 13:52:07 -0700

Hi Kevin, Tarun,

We are using the expansion connector A on Panda board to mount a SDIO 
WiFi dongle on MMC2 with a level triggered interrupt signal connected to 
GPIO 138. It's been working fine until 3.5 rc1. The board hang randomly 
within 5 mins during a network traffic test. After bisecting we found 
the culprit is "[PATCH 8/8] gpio/omap: fix missing check in 
*_runtime_suspend()" [1].

I noticed Kevin raised some similar cases on other platforms and also 
provided two patches in the patch mail thread. But unfortunately those 
two patches doesn't help in our case. I tested the driver with 3.5-rc3 
mainline kernel and the issue is still there. I can only "fix" the hang 
by either reverting the commit or disabling CONFIG_PM_RUNTIME. Also, the 
hang only happens on Panda ES board. Old Panda with 4430 works good.

Any thoughts and suggestions?

Thanks,
Franky

[1] http://article.gmane.org/gmane.linux.ports.arm.omap/75708/