From mboxrd@z Thu Jan 1 00:00:00 1970 From: Francois Romieu Subject: Re: r8169 64-bit DMA support Date: Tue, 22 Sep 2009 13:53:56 +0200 Message-ID: <20090922115356.GB13710@electric-eye.fr.zoreil.com> References: <4AB6BCEC.3070001@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev To: Robert Hancock Return-path: Received: from electric-eye.fr.zoreil.com ([213.41.134.224]:37580 "EHLO electric-eye.fr.zoreil.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756116AbZIVLs2 (ORCPT ); Tue, 22 Sep 2009 07:48:28 -0400 Content-Disposition: inline In-Reply-To: <4AB6BCEC.3070001@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: Robert Hancock : [...] > It's not clear (from the mails I've read) exactly what was going on in > the case that caused this to be added. Some AMD + r8169 systems simply did not work. > Normally these days the PCI subsystem is supposed to detect that DAC > isn't usable on a machine and refuse setting 64-bit DMA masks, it's > not the driver's responsibility to handle this. > I'm guessing that when this change was made that detection didn't exist > though. Not exactly. It was required for DAC to be explicitely enabled through the CPlusCmd register. > Thoughts on whether this default can be changed now ? The 8168 does not seem to need the CPlusCmd stuff. I'll check it but it should be possible to enable high DMA without condition for it. -- Ueimor