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Re: wbflush() abuse for TOSHIBA_RBTX4927

To: macro@ds2.pg.gda.pl
Subject: Re: wbflush() abuse for TOSHIBA_RBTX4927
From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Date: Wed, 16 Apr 2003 20:52:56 +0900 (JST)
Cc: kevink@mips.com, linux-mips@linux-mips.org, source@mvista.com
In-reply-to: <Pine.GSO.3.96.1030415180933.13254I-100000@delta.ds2.pg.gda.pl>
Organization: TOSHIBA Personal Computer System Corporation
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <00ae01c3035e$d431aba0$10eca8c0@grendel> <Pine.GSO.3.96.1030415180933.13254I-100000@delta.ds2.pg.gda.pl>
Sender: linux-mips-bounce@linux-mips.org
>>>>> On Tue, 15 Apr 2003 18:25:38 +0200 (MET DST), "Maciej W. Rozycki" 
>>>>> <macro@ds2.pg.gda.pl> said:
>> I remember that some of the Toshiba parts of the TX39 series
>> had some interesting quirks relating to the write buffer.  Perhaps
>> some of these were carried into the TX49 series as well?

macro> I suppose that's unrelated, since I'm specifically referring to
macro> the way the buffer is handled in the TOSHIBA_RBTX4927 code --
macro> the __wbflush() backend is not invoked by wbflush() and calls
macro> like mb() (used by portable drivers) unless the kernel is
macro> configured in an unobvious way and then there is duplicate
macro> "sync" (but maybe that's needed, thus my question among
macro> others).

I suppose it's just because the code was written before
CONFIG_CPU_HAS_SYNC was introduced.

AFAIK TX49's SYNC instruction correctly flushes the write buffer.
No bc0f loop is required.

---
Atsushi Nemoto

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