From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 20 May 2009 03:28:59 +0100 (BST) Received: from [222.92.8.141] ([222.92.8.141]:39944 "EHLO lemote.com" rhost-flags-FAIL-FAIL-OK-OK) by ftp.linux-mips.org with ESMTP id S20024846AbZETC2w (ORCPT ); Wed, 20 May 2009 03:28:52 +0100 Received: from localhost (localhost [127.0.0.1]) by lemote.com (Postfix) with ESMTP id 3640834058; Wed, 20 May 2009 10:23:57 +0800 (CST) X-Virus-Scanned: Debian amavisd-new at lemote.com Received: from lemote.com ([127.0.0.1]) by localhost (www.lemote.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 8O8B68Rr7Zxq; Wed, 20 May 2009 10:23:52 +0800 (CST) Received: from [172.16.2.16] (unknown [222.92.8.142]) by lemote.com (Postfix) with ESMTP id E83253404A; Wed, 20 May 2009 10:23:51 +0800 (CST) Subject: Re: [PATCH 26/30] loongson: flush irq write operation From: yanh Reply-To: yanh@lemote.com To: Ralf Baechle Cc: Wu Zhangjin , linux-mips@linux-mips.org, Arnaud Patard , loongson-dev@googlegroups.com, zhangfx@lemote.com, Philippe Vachon , Zhang Le , Erwan Lerale In-Reply-To: <20090519160117.GA19672@linux-mips.org> References: <1242426527.10164.174.camel@falcon> <20090518163603.GA22779@linux-mips.org> <1242700637.4382.21.camel@localhost.localdomain> <20090519160117.GA19672@linux-mips.org> Content-Type: text/plain; charset="UTF-8" Date: Wed, 20 May 2009 10:28:14 +0800 Message-Id: <1242786494.4382.58.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.24.1 (2.24.1-2.fc10) Content-Transfer-Encoding: 8bit Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 22833 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: yanh@lemote.com Precedence: bulk X-list: linux-mips 在 2009-05-19二的 17:01 +0100，Ralf Baechle写道： > On Tue, May 19, 2009 at 10:37:17AM +0800, yanh wrote: > > > > The semantic of inX() / outX() is defined by the x86 architecture which > > > forbids posting I/O port writes. In short I think this one is papering > > > over a bug in the outX() implementation. > > Yes, the outX should do a delayed write, however it does not. > > So our solution is making a read to flush the write. > > Do you actually need all the inb() you added to get things to work or is Thanks for your reply. As my test, if there is no the read, there will be many spurious irqs. > > diff --git a/arch/mips/kernel/i8259.c b/arch/mips/kernel/i8259.c > index 01c0885..42d75d7 100644 > --- a/arch/mips/kernel/i8259.c > +++ b/arch/mips/kernel/i8259.c > @@ -177,10 +177,12 @@ handle_real_irq: > outb(cached_slave_mask, PIC_SLAVE_IMR); > outb(0x60+(irq&7), PIC_SLAVE_CMD);/* 'Specific EOI' to slave */ > outb(0x60+PIC_CASCADE_IR, PIC_MASTER_CMD); /* 'Specific EOI' to master-IRQ2 */ > + inb(PIC_MASTER_CMD); > } else { > inb(PIC_MASTER_IMR); /* DUMMY - (do we need this?) */ > outb(cached_master_mask, PIC_MASTER_IMR); > outb(0x60+irq, PIC_MASTER_CMD); /* 'Specific EOI to master */ > + inb(PIC_MASTER_CMD); > } > smtc_im_ack_irq(irq); > spin_unlock_irqrestore(&i8259A_lock, flags); > > sufficient to solve the problem? I have test this patch just now. It works well on yeeloong. I have one question what's the difference between the two patch? > > Ralf