From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753209Ab2HMCfH (ORCPT ); Sun, 12 Aug 2012 22:35:07 -0400 Received: from cantor2.suse.de ([195.135.220.15]:55574 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752857Ab2HMCfG (ORCPT ); Sun, 12 Aug 2012 22:35:06 -0400 Date: Mon, 13 Aug 2012 12:34:53 +1000 From: NeilBrown To: balbi@ti.com Cc: Greg Kroah-Hartman , linux-usb@vger.kernel.org, linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Infinite looping in omap2430.c USB driver Message-ID: <20120813123453.4cba14ca@notabene.brown> In-Reply-To: <20120809111549.GT12174@arwen.pp.htv.fi> References: <20120707083949.2cf91eeb@notabene.brown> <20120809111549.GT12174@arwen.pp.htv.fi> X-Mailer: Claws Mail 3.7.10 (GTK+ 2.24.7; x86_64-suse-linux-gnu) Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/IAnIF=EIPIm1aK7eCXcbeMK"; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Sig_/IAnIF=EIPIm1aK7eCXcbeMK Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Thu, 9 Aug 2012 14:15:51 +0300 Felipe Balbi wrote: > hehe, that's nasty. Please send a patch converting to a try count and a > udelay_range(), or something. >=20 how's this? Thanks, NeilBrown From: NeilBrown 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 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 #include #include +#include =20 #include "musb_core.h" #include "omap2430.h" @@ -145,6 +146,7 @@ static void omap2430_musb_set_vbus(struct musb *musb, i= nt is_on) =20 if (is_on) { if (musb->xceiv->state =3D=3D OTG_STATE_A_IDLE) { + int loops =3D 100; /* start the session */ devctl |=3D 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) { =20 + mdelay(5); cpu_relax(); =20 - if (time_after(jiffies, timeout)) { + if (time_after(jiffies, timeout) + || loops-- <=3D 0) { dev_err(musb->controller, "configured as A device timeout"); ret =3D -EINVAL; --Sig_/IAnIF=EIPIm1aK7eCXcbeMK Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIVAwUBUChnzTnsnt1WYoG5AQK+fBAAlv2n740UiFMpfbLBf2OLnfnHsTcy1WVE KTuJL4sJroEW6u17Z9DaZ8Fh7IHN+zqZfgzR7H54x5V4sx7DtEFU5vAM6hzB96r9 SkglQKvwYD9XCq8Oqfod9ru6/g0zptH1oVbV1vLA54RwU6EbZpo7KSGjnNHRrp+Y lUKfYw39T1JKmZsFmcbP9ZUAFButXFGsYs0KRFrBVziHc8xFBY031LXLmWtSLyI+ fMC/R4rn+dAdCpWSVt2WTxyiiz6wEY7ynNG3TBHGtG22Vsw3EZM37ViBN+857FQL M/tL8nSKbHC3OF01AVwsssjS1ce/sNyYs0M0MbT0n0B6p1XDxnMLG4sfFd5N7j8a Bj2eIBKJcOwKsOchbJLlOy7Qu7NzwXAT64bR8v7goEO0LmLs1hZeRaqFuCCU2Etb xLAPvG4JwUSKehvQw2R8yG9uiSuYGfPR0m3Wv9r9UUOzo/BS8ZXqBJY3A0WaUxy8 +ly3IITsCQmptwSGv9itbnCZDxIUZwDYLLP86zFfyargf93v7UJIvSeKibybzM8Z 2g51OxcLrMfNmuyAtxA6yC/X+de4PZzmZG4w8Ce8+27k2YNSLn+oOdKM6japMPms CejNOKqXbD1KK6qkrlMGnHORD8SPEoxvooIJoOrIHwYhOmnCXcEjzFlMhS1LjqAy P6r3UFoiZcs= =mWBd -----END PGP SIGNATURE----- --Sig_/IAnIF=EIPIm1aK7eCXcbeMK--