From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.datangmobile.cn (mail.datangmobile.cn [219.142.67.62]) by ozlabs.org (Postfix) with ESMTP id 9E605DDE1F for ; Wed, 18 Feb 2009 16:47:46 +1100 (EST) MIME-Version: 1.0 Content-Type: text/plain; charset="gb2312" Subject: Re: [PATCH] fix the interrupt loss problem on powerpc IPIC(2.6.25-2.6.28) Date: Wed, 18 Feb 2009 13:47:42 +0800 Message-ID: From: To: Cc: linuxppc-dev@ozlabs.org, leoli@freescale.com, linux-kernel@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , renew description in the patch, with this change the 'temp' is still = used to make code clear. ___________________________________________ From: Da Yu Date: Wed, 18 Feb 2009 19:58:20 +0800 Subject: [PATCH] fix the interrupt loss problem on powerpc IPIC = (2.6.25-2.6.28) Description: The interrupt pending register is write 1 clear. If there = are more than one external interrupts pending at the same time, acking = the first interrupt by reading pending register then OR the = corresponding bit and write back to pending register will also clear = other interrupt pending bits. That will cause loss of interrupt. Signed-off-by: Da Yu --- --- a/arch/powerpc/sysdev/ipic.c 2009-02-18 09:47:04.000000000 +0800 +++ b/arch/powerpc/sysdev/ipic.c 2009-02-18 09:46:34.000000000 +0800 @@ -568,8 +568,7 @@ static void ipic_ack_irq(unsigned int vi spin_lock_irqsave(&ipic_lock, flags); - temp =3D ipic_read(ipic->regs, ipic_info[src].ack); - temp |=3D (1 << (31 - ipic_info[src].bit)); + temp =3D 1 << (31 - ipic_info[src].bit); ipic_write(ipic->regs, ipic_info[src].ack, temp); /* mb() can't guarantee that ack is finished. But it does finish @@ -592,8 +591,7 @@ static void ipic_mask_irq_and_ack(unsign temp &=3D ~(1 << (31 - ipic_info[src].bit)); ipic_write(ipic->regs, ipic_info[src].mask, temp); - temp =3D ipic_read(ipic->regs, ipic_info[src].ack); - temp |=3D (1 << (31 - ipic_info[src].bit)); + temp =3D 1 << (31 - ipic_info[src].bit); ipic_write(ipic->regs, ipic_info[src].ack, temp); /* mb() can't guarantee that ack is finished. But it does finish =20 =20 -----=D3=CA=BC=FE=D4=AD=BC=FE----- =B7=A2=BC=FE=C8=CB: Olof Johansson [mailto:olof@lixom.net]=20 =B7=A2=CB=CD=CA=B1=BC=E4: 2009=C4=EA2=D4=C218=C8=D5 10:43 =CA=D5=BC=FE=C8=CB: =F3=CE=D3=ED =B3=AD=CB=CD: leoli@freescale.com; galak@kernel.crashing.org; = linuxppc-dev@ozlabs.org; linux-kernel@vger.kernel.org =D6=F7=CC=E2: Re: [PATCH] fix the interrupt loss problem on powerpc = IPIC(2.6.25-2.6.28) On Wed, Feb 18, 2009 at 10:16:07AM +0800, dayu@datangmobile.cn wrote: > From: Da Yu > Date: Wed, 18 Feb 2009 19:58:20 +0800 > Subject: [PATCH] fix the interrupt loss problem on powerpc IPIC=20 > (2.6.25-2.6.28) >=20 > Signed-off-by: Da Yu Still no proper explanation in the patch. Also, with this change, is 'temp' really needed, or can you just pass in = the mask by hand? -Olof > --- >=20 > --- a/arch/powerpc/sysdev/ipic.c 2009-02-18 09:47:04.000000000 +0800 > +++ b/arch/powerpc/sysdev/ipic.c 2009-02-18 09:46:34.000000000 +0800 > @@ -568,8 +568,7 @@ static void ipic_ack_irq(unsigned int vi >=20 > spin_lock_irqsave(&ipic_lock, flags); >=20 > - temp =3D ipic_read(ipic->regs, ipic_info[src].ack); > - temp |=3D (1 << (31 - ipic_info[src].bit)); > + temp =3D 1 << (31 - ipic_info[src].bit); > ipic_write(ipic->regs, ipic_info[src].ack, temp); >=20 > /* mb() can't guarantee that ack is finished. But it does finish