On Tue, Aug 14, 2012 at 07:46:59AM +1000, NeilBrown wrote:

On Mon, 13 Aug 2012 17:32:34 +0300 Felipe Balbi [off-list ref] wrote:

quoted

Hi,

On Mon, Aug 13, 2012 at 12:34:53PM +1000, NeilBrown wrote:

quoted

On Thu, 9 Aug 2012 14:15:51 +0300 Felipe Balbi [off-list ref] wrote:

quoted

hehe, that's nasty. Please send a patch converting to a try count and a
udelay_range(), or something.

how's this?

Thanks,
NeilBrown


From: NeilBrown <redacted>
Date: Mon, 13 Aug 2012 12:32:58 +1000
Subject: [PATCH] omap2430: don't loop indefinitely in interrupt.

When called during resume_irqs, omap2430_musb_set_vbus() is run with
interrupts disabled,  In that case 'jiffies' never changes so the loop
can loop forever.

So impose a maximum loop count and add an 'mdelay' to ensure we wait
a reasonable amount of time for bit to be cleared.

This fixes a hang on resume.

Signed-of-by: NeilBrown [off-list ref]

diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c
index c7785e8..8a93381 100644
--- a/drivers/usb/musb/omap2430.c
+++ b/drivers/usb/musb/omap2430.c

@@ -34,6 +34,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/pm_runtime.h>
 #include <linux/err.h>
+#include <linux/delay.h>
 
 #include "musb_core.h"
 #include "omap2430.h"

@@ -145,6 +146,7 @@ static void omap2430_musb_set_vbus(struct musb *musb, int is_on)
 
 	if (is_on) {
 		if (musb->xceiv->state == OTG_STATE_A_IDLE) {
+			int loops = 100;
 			/* start the session */
 			devctl |= MUSB_DEVCTL_SESSION;
 			musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);

@@ -154,9 +156,11 @@ static void omap2430_musb_set_vbus(struct musb *musb, int is_on)
 			 */
 			while (musb_readb(musb->mregs, MUSB_DEVCTL) & 0x80) {
 
+				mdelay(5);

I would prefer udelay_range() as it will let scheduler group timers.
Something like:

udelay_range(3000, 5000);

should do, I gues...

Except that there is no udelay_range :-(
There is a usleep_range, but that can only be used from non-atomic context
and in the problem case interrupts are disabled and a spinlock is held so we

my bad. Got confused. I will apply the original patch then. Thanks.

-- 
balbi