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From: Ralf Baechle <ralf@linux-mips.org>
To: yanh <yanh@lemote.com>
Cc: Wu Zhangjin <wuzhangjin@gmail.com>,
	linux-mips@linux-mips.org, Arnaud Patard <apatard@mandriva.com>,
	loongson-dev@googlegroups.com, zhangfx@lemote.com,
	Philippe Vachon <philippe@cowpig.ca>,
	Zhang Le <r0bertz@gentoo.org>, Erwan Lerale <erwan@thiscow.com>
Subject: Re: [PATCH 26/30] loongson: flush irq write operation
Date: Wed, 20 May 2009 08:07:19 +0100	[thread overview]
Message-ID: <20090520070719.GA24231@linux-mips.org> (raw)
In-Reply-To: <1242786494.4382.58.camel@localhost.localdomain>

On Wed, May 20, 2009 at 10:28:14AM +0800, yanh wrote:

> I have test this patch just now. It works well on yeeloong. 

Thanks for testing.

> I have one question what's the difference between the two patch? 

Uncached writes can't be re-ordered.  By adding a read after the last
write my patch forces not only completion of the preceding write but due
to this ordering constraint also completion of all preceding writes is
enforced.

I/O space writes are slow.  I mean slower than slugs in space.  So my
patch is an optimization but that was not the point; I really only meant
to verify that we understood what's going on and we seem to.  Now let's
fix the real issue and make outX() non-posted.

  Ralf

  parent reply	other threads:[~2009-05-20  7:08 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-15 22:28 [PATCH 26/30] loongson: flush irq write operation Wu Zhangjin
2009-05-15 22:28 ` Wu Zhangjin
2009-05-18 16:36 ` Ralf Baechle
2009-05-19  2:37   ` yanh
2009-05-19 16:01     ` Ralf Baechle
2009-05-20  2:28       ` yanh
2009-05-20  3:07         ` yanh
2009-05-20  7:07         ` Ralf Baechle [this message]
2009-05-20  7:58           ` yanh

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