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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 C48CAC432C0 for ; Mon, 2 Dec 2019 17:00:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 987022464D for ; Mon, 2 Dec 2019 17:00:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="jin1Ceu8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727702AbfLBRAQ (ORCPT ); Mon, 2 Dec 2019 12:00:16 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:39990 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727493AbfLBRAQ (ORCPT ); Mon, 2 Dec 2019 12:00:16 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=G2ll8x21H3OwfR6X73OWEUXv71XKn2fRqBpOxb8mfV8=; b=jin1Ceu89T016/r57qJ2013T1 hr1+t0iWlp+orW8JGDLHPv23c8AqgtSjLpocGr/ZnxxnFPEr74z/yAfYrJYh6c097LzAzkhZb+CRW iZpTGwMLzjCXcK90KmToPX6phwgXBVCTTpAIDVhcL4kmMwKb23mqiUrL5xWRAoJD3Kkk//jAYfqFH zt0ZtF+d8xP5Kp8S2ve+ptn9bOC1kWdkBeaI6set11hILW3ZWuNX8VguaykW67r3nZZrfRPhPvOmJ G4M94kGTyCgt81ywBOrEXIo6VSlxxmeRzQi/yhZf+S6Gq6nvcYSVJXMPb148ryREcJHx4jwPvMbOw MCiah4RJQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1ibp3T-0000jZ-A1; Mon, 02 Dec 2019 17:00:11 +0000 Date: Mon, 2 Dec 2019 09:00:11 -0800 From: Christoph Hellwig To: Kai-Heng Feng Cc: joro@8bytes.org, Alex Deucher , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] iommu/amd: Disable IOMMU on Stoney Ridge systems Message-ID: <20191202170011.GC30032@infradead.org> References: <20191129142154.29658-1-kai.heng.feng@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191129142154.29658-1-kai.heng.feng@canonical.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 29, 2019 at 10:21:54PM +0800, Kai-Heng Feng wrote: > Serious screen flickering when Stoney Ridge outputs to a 4K monitor. > > According to Alex Deucher, IOMMU isn't enabled on Windows, so let's do > the same here to avoid screen flickering on 4K monitor. Disabling the IOMMU entirely seem pretty severe. Isn't it enough to identity map the GPU device? 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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 53038C432C3 for ; Mon, 2 Dec 2019 17:00:19 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1F87E20848 for ; Mon, 2 Dec 2019 17:00:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="jin1Ceu8" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1F87E20848 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id ECED92154A; Mon, 2 Dec 2019 17:00:18 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id tkEBs-or0OfB; Mon, 2 Dec 2019 17:00:18 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by silver.osuosl.org (Postfix) with ESMTP id 94A252152A; Mon, 2 Dec 2019 17:00:18 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 81F10C1797; Mon, 2 Dec 2019 17:00:18 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 2B6F8C087F for ; Mon, 2 Dec 2019 17:00:17 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 2471288687 for ; Mon, 2 Dec 2019 17:00:17 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id gROoy4+icjr2 for ; Mon, 2 Dec 2019 17:00:15 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by hemlock.osuosl.org (Postfix) with ESMTPS id DCA2B88187 for ; Mon, 2 Dec 2019 17:00:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=G2ll8x21H3OwfR6X73OWEUXv71XKn2fRqBpOxb8mfV8=; b=jin1Ceu89T016/r57qJ2013T1 hr1+t0iWlp+orW8JGDLHPv23c8AqgtSjLpocGr/ZnxxnFPEr74z/yAfYrJYh6c097LzAzkhZb+CRW iZpTGwMLzjCXcK90KmToPX6phwgXBVCTTpAIDVhcL4kmMwKb23mqiUrL5xWRAoJD3Kkk//jAYfqFH zt0ZtF+d8xP5Kp8S2ve+ptn9bOC1kWdkBeaI6set11hILW3ZWuNX8VguaykW67r3nZZrfRPhPvOmJ G4M94kGTyCgt81ywBOrEXIo6VSlxxmeRzQi/yhZf+S6Gq6nvcYSVJXMPb148ryREcJHx4jwPvMbOw MCiah4RJQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1ibp3T-0000jZ-A1; Mon, 02 Dec 2019 17:00:11 +0000 Date: Mon, 2 Dec 2019 09:00:11 -0800 From: Christoph Hellwig To: Kai-Heng Feng Subject: Re: [PATCH v2] iommu/amd: Disable IOMMU on Stoney Ridge systems Message-ID: <20191202170011.GC30032@infradead.org> References: <20191129142154.29658-1-kai.heng.feng@canonical.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191129142154.29658-1-kai.heng.feng@canonical.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Cc: Alex Deucher , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Fri, Nov 29, 2019 at 10:21:54PM +0800, Kai-Heng Feng wrote: > Serious screen flickering when Stoney Ridge outputs to a 4K monitor. > > According to Alex Deucher, IOMMU isn't enabled on Windows, so let's do > the same here to avoid screen flickering on 4K monitor. Disabling the IOMMU entirely seem pretty severe. Isn't it enough to identity map the GPU device? _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu