From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH 2/2] ACPICA: support Generic Address Structure bit_offset in acpi_read/write Date: Thu, 17 Nov 2011 21:27:40 +0100 Message-ID: <201111172127.40664.rjw@sisk.pl> References: <20111111230347.20897.28797.stgit@bhelgaas.mtv.corp.google.com> <201111170027.14509.rjw@sisk.pl> <1321491083.13860.93.camel@yhuang-dev> Mime-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from ogre.sisk.pl ([217.79.144.158]:44586 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754871Ab1KQUY5 (ORCPT ); Thu, 17 Nov 2011 15:24:57 -0500 In-Reply-To: <1321491083.13860.93.camel@yhuang-dev> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Huang Ying Cc: Bjorn Helgaas , Thomas Renninger , Len Brown , "Moore, Robert" , "linux-acpi@vger.kernel.org" , "bondd@us.ibm.com" , Myron Stowe On Thursday, November 17, 2011, Huang Ying wrote: > On Thu, 2011-11-17 at 07:27 +0800, Rafael J. Wysocki wrote: > > On Wednesday, November 16, 2011, Bjorn Helgaas wrote: > > > On Tue, Nov 15, 2011 at 9:49 AM, Thomas Renninger wrote: > > > > On Tuesday, November 15, 2011 04:13:15 PM Bjorn Helgaas wrote: > > > >> On Fri, Nov 11, 2011 at 4:05 PM, Bjorn Helgaas wrote: > > > >> > acpi_read(), acpi_write(), acpi_hw_read(), and acpi_hw_write() currently > > > >> > ignore the GAS bit_offset field (but they do warn if it is non-zero). > > > >> > > > > >> > APEI tables are starting to use non-zero bit_offsets. APEI uses > > > >> > special-purpose apei_exec_read_register() and apei_exec_write_register() > > > >> > interfaces that apply the bit_offset. > > > >> > > > > >> > This patch adds bit_offset support to the generic interfaces, which is > > > >> > one small step toward using them instead of the special-purpose APEI ones. > > > >> > > > >> Eww, brown paper bag time. Just pretend you never saw this lame > > > >> implementation attempt. > > > >> > > > >> I do think we need to make acpi_read() smart enough to extract a bit > > > >> field, but this try doesn't work. > > > > > > > > As a first step it would be great if Ying's and Myron's patches which > > > > afaik conflict get serialized and pushed into an "acpi branch". > > > > What the status there? > > > > > > Ying's patch ("Add RAM mapping support") fixes a real issue with using > > > EINJ, so we need to do something with it. > > > > I kind of agree, but I wonder if page_is_ram() is the right check? > > page_is_ram() is used by x86 ioremap implementation to exclude RAM > range. So I think it can be used here. Except that ACPI is not going to be x86-specific any more in the (near?) future. Have you taken that into consideration? Rafael