From owner-freebsd-arm@FreeBSD.ORG Sun May 11 06:23:45 2014 Return-Path: Delivered-To: freebsd-arm@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 1C9A3E7B; Sun, 11 May 2014 06:23:45 +0000 (UTC) Received: from mail.turbocat.net (heidi.turbocat.net [88.198.202.214]) (using TLSv1.1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id C321326F6; Sun, 11 May 2014 06:23:43 +0000 (UTC) Received: from laptop015.home.selasky.org (cm-176.74.213.204.customer.telag.net [176.74.213.204]) (using TLSv1 with cipher ECDHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by mail.turbocat.net (Postfix) with ESMTPSA id 1BBB61FE02B; Sun, 11 May 2014 08:23:41 +0200 (CEST) Message-ID: <536F17A1.8060807@selasky.org> Date: Sun, 11 May 2014 08:24:33 +0200 From: Hans Petter Selasky User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Ian Lepore Subject: Re: USB isochronous traffic with Rasberry Pi [WAS: Re: USB audio device on Raspberry Pi] References: <20140425154430.GA76168@utility-01.thismonkey.com> <5362638B.1080104@selasky.org> <5363C133.2000304@selasky.org> <53677CB8.5000800@selasky.org> <1399303695.22079.239.camel@revolution.hippie.lan> <1399304157.22079.243.camel@revolution.hippie.lan> <5368A93D.3070608@selasky.org> <5368AC03.8080401@selasky.org> <536CE5E9.8020408@selasky.org> <1399647986.22079.367.camel@revolution.hippie.lan> <536D0575.1040407@selasky.org> <1399661378.22079.376.camel@revolution.hippie.lan> <536DDA6D.7060101@selasky.org> <1399724697.22079.386.camel@revolution.hippie.l an> <536E2EBB.7030104@selasky.org> <1399742062.22079.403.camel@revolution.hippie.lan> <536EA597.3070700@selasky.org> <536EA753.40905@selasky.org> <1399764190.22079.425.camel@revolution.hippie.lan> In-Reply-To: <1399764190.22079.425.camel@revolution.hippie.lan> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "freebsd-arm@freebsd.org" , Alexander Motin X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 May 2014 06:23:45 -0000 On 05/11/14 01:23, Ian Lepore wrote: > On Sun, 2014-05-11 at 00:25 +0200, Hans Petter Selasky wrote: >> Hi, >> >> This patch fixes the problem too: >> >> diff --git a/sys/arm/arm/machdep.c b/sys/arm/arm/machdep.c >> index 0490be7..8d53fab 100644 >> --- a/sys/arm/arm/machdep.c >> +++ b/sys/arm/arm/machdep.c >> @@ -432,8 +432,12 @@ cpu_idle(int busy) >> cpu_idleclock(); >> } >> #endif >> + register_t s; >> + s = intr_disable(); >> if (!sched_runnable()) >> cpu_sleep(0); >> + intr_restore(s); >> + >> #ifndef NO_EVENTTIMERS >> if (!busy) { >> cpu_activeclock(); >> >> It appears some IRQ is happening when sched_runnable() is running, and >> then cpu_sleep(0) is executed even though sched_runnable() is no longer >> true. >> >> --HPS > > Aha! Now I think you're on to something. Even after explaining why > interrupts should be disabled for WFI I didn't notice that we don't > disable interrupts before WFI. (I wonder if this is why I sometimes see > a lost timer interrupt and have to hit a key to un-wedge things.) > > Can you try the attached? The spinlock_enter/exit calls are essentially > a combination of disabling interrupts and doing a critical_enter(). > > -- Ian Hi Ian, Your patch works! BTW: I see the "mips" platform might have a similar issue. --HPS