From: NeilBrown <neilb@suse.de>
To: balbi@ti.com
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-usb@vger.kernel.org, linux-omap@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: Infinite looping in omap2430.c USB driver
Date: Mon, 13 Aug 2012 12:34:53 +1000 [thread overview]
Message-ID: <20120813123453.4cba14ca@notabene.brown> (raw)
In-Reply-To: <20120809111549.GT12174@arwen.pp.htv.fi>
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On Thu, 9 Aug 2012 14:15:51 +0300 Felipe Balbi <balbi@ti.com> wrote:
> 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 <neilb@suse.de>
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 <neilb@suse.de>
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);
cpu_relax();
- if (time_after(jiffies, timeout)) {
+ if (time_after(jiffies, timeout)
+ || loops-- <= 0) {
dev_err(musb->controller,
"configured as A device timeout");
ret = -EINVAL;
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next prev parent reply other threads:[~2012-08-13 2:35 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-06 22:39 Infinite looping in omap2430.c USB driver NeilBrown
2012-07-09 8:32 ` Tony Lindgren
2012-07-30 0:16 ` NeilBrown
2012-08-09 11:15 ` Felipe Balbi
2012-08-13 2:34 ` NeilBrown [this message]
2012-08-13 14:32 ` Felipe Balbi
2012-08-13 21:46 ` NeilBrown
2012-08-14 7:58 ` Felipe Balbi
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