From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from oss.sgi.com (localhost.localdomain [127.0.0.1]) by oss.sgi.com (8.12.3/8.12.3) with ESMTP id g3FIfC8d008193 for ; Mon, 15 Apr 2002 11:41:12 -0700 Received: (from majordomo@localhost) by oss.sgi.com (8.12.3/8.12.3/Submit) id g3FIfCjQ008192 for linux-mips-outgoing; Mon, 15 Apr 2002 11:41:12 -0700 X-Authentication-Warning: oss.sgi.com: majordomo set sender to owner-linux-mips@oss.sgi.com using -f Received: from ayrnetworks.com (64-166-72-141.ayrnetworks.com [64.166.72.141]) by oss.sgi.com (8.12.3/8.12.3) with SMTP id g3FIf98d008182 for ; Mon, 15 Apr 2002 11:41:10 -0700 Received: (from wjhun@localhost) by ayrnetworks.com (8.11.2/8.11.2) id g3FIciu21802 for linux-mips@oss.sgi.com; Mon, 15 Apr 2002 11:38:44 -0700 Date: Mon, 15 Apr 2002 11:38:44 -0700 From: William Jhun To: linux-mips@oss.sgi.com Subject: rm7k flush_icache_line() in rm7k_dma_cache_* Message-ID: <20020415113844.A21747@ayrnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i Sender: owner-linux-mips@oss.sgi.com Precedence: bulk Hello, We've been experiencing some problems with our RM7k cache code which is based on the sgi mm/rm7k.c from around kernel version 2.4.2. While trying to track this down, we noticed that someone added a call to flush_icache_line() in the rm7k_dma_cache_*() routines (now mm/c-rm7k.c). What is the reason for this? It is our understanding that the instruction cache does not write back, and so stale cache lines in the icache which are later used for data/dma would seem innocuous. Is this not true? We could not find a CVS log entry to explain this, either. Did anyone experience problems without these calls to flush_icache_line()? Thanks, Will