From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E8489C2D0A3 for ; Fri, 6 Nov 2020 15:22:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D3C1208C7 for ; Fri, 6 Nov 2020 15:22:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727562AbgKFPWH (ORCPT ); Fri, 6 Nov 2020 10:22:07 -0500 Received: from foss.arm.com ([217.140.110.172]:40668 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727558AbgKFPWH (ORCPT ); Fri, 6 Nov 2020 10:22:07 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A1C2914BF; Fri, 6 Nov 2020 07:22:06 -0800 (PST) Received: from [192.168.1.179] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 419073F66E; Fri, 6 Nov 2020 07:22:03 -0800 (PST) Subject: Re: [RFC PATCH 0/4] ACPI/IORT: Support for IORT RMR node To: Shameerali Kolothum Thodi , "linux-arm-kernel@lists.infradead.org" , "linux-acpi@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "devel@acpica.org" Cc: "lorenzo.pieralisi@arm.com" , "joro@8bytes.org" , Jonathan Cameron , Linuxarm , "Guohanjun (Hanjun Guo)" , Sami Mujawar , "robin.murphy@arm.com" , wanghuiqiang References: <20201027112646.44680-1-shameerali.kolothum.thodi@huawei.com> <36e3a0e58e334e6aa3c051000d742543@huawei.com> From: Steven Price Message-ID: Date: Fri, 6 Nov 2020 15:22:03 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <36e3a0e58e334e6aa3c051000d742543@huawei.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On 28/10/2020 18:24, Shameerali Kolothum Thodi wrote: > Hi Steve, > >> -----Original Message----- >> From: Steven Price [mailto:steven.price@arm.com] >> Sent: 28 October 2020 16:44 >> To: Shameerali Kolothum Thodi ; >> linux-arm-kernel@lists.infradead.org; linux-acpi@vger.kernel.org; >> iommu@lists.linux-foundation.org; devel@acpica.org >> Cc: lorenzo.pieralisi@arm.com; joro@8bytes.org; Jonathan Cameron >> ; Linuxarm ; >> Guohanjun (Hanjun Guo) ; robin.murphy@arm.com; >> wanghuiqiang ; Sami Mujawar >> >> Subject: Re: [RFC PATCH 0/4] ACPI/IORT: Support for IORT RMR node >> >> On 27/10/2020 11:26, Shameer Kolothum wrote: >>> The series adds support to IORT RMR nodes specified in IORT >>> Revision E -ARM DEN 0049E[0]. RMR nodes are used to describe memory >>> ranges that are used by endpoints and require a unity mapping >>> in SMMU. >> >> Hi Shameer, >> >> I've also been taking a look at RMR, and Sami is helping me get set up >> so that I can do some testing. We're hoping to be able to test an EFI >> framebuffer or splash screen - which has the added complication of the >> unity mapping becoming redundant if a native display driver takes over >> the display controller. >> >> I've looked through your series and the code looks correct to me. > > Thanks for taking a look and the details. > >> Hopefully I'll be able to give it some testing soon. > > Cool. Please update once you get a chance run the tests. Hi Shameer, Just to update on this, for the EFI framebuffer use case I hit exactly the issue that Robin has mentioned in another thread - the RMR is effectively ignored because the display controller isn't being handled by Linux (so there's no device to link it to). The splash screen might similarly flicker as the SMMU reset will initially block the traffic before the RMR region is enabled. Steve