From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934207AbeCHEON (ORCPT ); Wed, 7 Mar 2018 23:14:13 -0500 Received: from mx2.suse.de ([195.135.220.15]:45145 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750761AbeCHEOM (ORCPT ); Wed, 7 Mar 2018 23:14:12 -0500 Date: Thu, 8 Mar 2018 04:14:11 +0000 From: "Luis R. Rodriguez" To: "Luis R. Rodriguez" , Andy Lutomirski Cc: "French, Nicholas A." , "hans.verkuil@cisco.com" , "linux-kernel@vger.kernel.org" , "linux-media@vger.kernel.org" Subject: Re: ivtv: use arch_phys_wc_add() and require PAT disabled Message-ID: <20180308041411.GR14069@wotan.suse.de> References: <20180301171936.GU14069@wotan.suse.de> <20180307190205.GA14069@wotan.suse.de> <20180308040601.GQ14069@wotan.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180308040601.GQ14069@wotan.suse.de> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 08, 2018 at 04:06:01AM +0000, Luis R. Rodriguez wrote: > On Thu, Mar 08, 2018 at 03:16:29AM +0000, French, Nicholas A. wrote: > > On Wed, Mar 07, 2018 at 07:02:05PM +0000, Luis R. Rodriguez wrote: > > > On Tue, Mar 06, 2018 at 09:01:10PM +0000, French, Nicholas A. wrote: > > > > any reason why PAT can't be enabled for ivtvfb as simply as in the attached > > > > patch? > > > > > > Prior to your change the OSD buffer was obtained using the itv->dec_mem + oi->video_rbase > > > given itv->dec_mem was initialized via [...] > > > itv->dec_mem = ioremap_nocache(itv->base_addr + IVTV_DECODER_OFFSET - oi->video_buffer_size, > > > IVTV_DECODER_SIZE); > > > > Ah, I see. So my proposed ioremap_wc call was only "working" by aliasing the > > ioremap_nocache()'d mem area and not actually using write combining at all. > > There are some debugging PAT toys out there I think but I haven't played with > them yet or I forgot how to to confirm or deny this sort of effort, but > likeley. In fact come to think of it I believe some neurons are telling me that if two type does not match we'd get an error? Luis