From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH] serial: Flush posted write on 34xx to make 8250 work (Re: What happened to the serial console on BeagleBoard with 2.6.28-rc2?) Date: Mon, 3 Nov 2008 08:45:18 -0800 Message-ID: <20081103164516.GT28924@atomide.com> References: <200811021126.13514.david-b@pacbell.net> <20081102205019.GJ28924@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mho-01-bos.mailhop.org ([63.208.196.178]:52229 "EHLO mho-01-bos.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756639AbYKCQp1 (ORCPT ); Mon, 3 Nov 2008 11:45:27 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Ming Lei Cc: David Brownell , rick@efn.org, linux-omap@vger.kernel.org, nmonson@gmail.com, felipe.contreras@gmail.com * Ming Lei [081103 04:59]: > 2008/11/3 Tony Lindgren : > > * David Brownell [081102 11:26]: > >> On Sunday 02 November 2008, Rick Bronson wrote: > >> > > Is that what you saw too? > >> > > >> > Yep, that's what I saw, but only if I had DEBUG_LL=y. Without that > >> > I had nothing except "Uncompressing Linux........". > >> > >> I don't have DEBUG_LL=y ... if you had some kind of network > >> link configured over USB, could you SSH in? (I can.) > >> > >> > >> > I guess we don't see this problem on the other 2 ports since they > >> > are mapped MT_MEMORY_SO and not MT_DEVICE (L4_34XX_PHYS). > >> > >> Hmm, inconsistency is to be avoided. :) > >> > >> I wonder what the root cause is ... is the driver missing > >> various barriers needed to make MT_DEVICE work? Or is the > >> MT_DEVICE incorrect in the first place? "git whatchanged" > >> didn't show any recent changes that seemed (on a quick > >> glance) to affect I/O at that level. Maybe it was one of > >> the other TTY changes interacting here. > > > > Yeah I don't know what may have changed, or have things just > > gotten faster now with cortex since 2.6.27? > > > > Anyways, this patch fixes the issue for me without marking > > things strongly ordered. Rick, does this work for you? > > This patch still works for me. > Thanks! Well the real problem has been found, there's a bug with the recent ptebits patches, which causes section mappings to be just MT_MEMORY instead of MT_DEVICE.. So let's put things on hold until we have a real fix for that on the linux-arm-kernel mailing list, hopefully today. Regards, Tony