From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from oss.sgi.com (localhost [127.0.0.1]) by oss.sgi.com (8.12.3/8.12.3) with ESMTP id g54HfDnC002316 for ; Tue, 4 Jun 2002 10:41:13 -0700 Received: (from majordomo@localhost) by oss.sgi.com (8.12.3/8.12.3/Submit) id g54HfD4B002315 for linux-mips-outgoing; Tue, 4 Jun 2002 10:41:13 -0700 X-Authentication-Warning: oss.sgi.com: majordomo set sender to owner-linux-mips@oss.sgi.com using -f Received: from t111.niisi.ras.ru (t111.niisi.ras.ru [193.232.173.111]) by oss.sgi.com (8.12.3/8.12.3) with SMTP id g54Hf5nC002310 for ; Tue, 4 Jun 2002 10:41:07 -0700 Received: from t06.niisi.ras.ru (t06.niisi.ras.ru [193.232.173.6]) by t111.niisi.ras.ru (8.9.1/8.9.1) with ESMTP id VAA07238; Tue, 4 Jun 2002 21:43:01 +0400 Received: (from uucp@localhost) by t06.niisi.ras.ru (8.7.6/8.7.3) with UUCP id VAA13814; Tue, 4 Jun 2002 21:38:21 +0400 Received: from niisi.msk.ru (t34 [193.232.173.34]) by niisi.msk.ru (8.8.8/8.8.8) with ESMTP id VAA07610; Tue, 4 Jun 2002 21:40:15 +0400 (MSK) Message-ID: <3CFCFC79.E846226B@niisi.msk.ru> Date: Tue, 04 Jun 2002 21:44:25 +0400 From: "Gleb O. Raiko" Organization: NIISI RAN X-Mailer: Mozilla 4.79 [en] (WinNT; U) X-Accept-Language: en,ru MIME-Version: 1.0 To: "Maciej W. Rozycki" CC: Ralf Baechle , linux-mips@fnet.fr, linux-mips@oss.sgi.com Subject: Re: [patch] linux: mb() and friends again References: Content-Type: text/plain; charset=koi8-r Content-Transfer-Encoding: 7bit Sender: owner-linux-mips@oss.sgi.com Precedence: bulk "Maciej W. Rozycki" wrote: > > Why did you drop it? It's definetely required. > > Nope, it wasn't dropped. It's included in a different patch, namely > "patch-mips-2.4.18-20020412-wbflush-5". The patch depends on the > "patch-mips-2.4.18-20020530-mb-wb-8" one, so I am not going to resubmit > the former one for discussion here until (unless) we decide on the latter > one. Don't forget the latter one. :-) > > > While you patch operates in unusual terms from hw point of view, it does > > right thins by stating that external wbs do differ from internal wb. > > What do you mean by "unusual terms"? The names of the macros? Well, > they are based on what's used for other platforms and if treated as > abstract names (as they should be) they actually reflect reality. > Basically, the patch logically allows combination of a CPU with internal write-buffer and an external wb chip. It's impossible if hw designers don't smoke hard. :-) In fact, CONFIG_CPU_HAS_WB means !CONFIG_CPU_HAS_WB, i.e. CPU don't have built-in write-buffer logic and there is an external write-buffer chip somewhere in the box. ("Somewhere" means a place on the path from the local bus to a memory controller.) Then, __fast_iob just flushes internal wb while wbflush flushes an external wb. That's why I call it "unusual terms from hw POV". But, don't reimplement the patch, please. It's OK. Just from software point of view. Regards, Gleb.