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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 87830C43387 for ; Fri, 4 Jan 2019 01:06:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6197D217F5 for ; Fri, 4 Jan 2019 01:06:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727465AbfADBG1 (ORCPT ); Thu, 3 Jan 2019 20:06:27 -0500 Received: from dcvr.yhbt.net ([64.71.152.64]:50684 "EHLO dcvr.yhbt.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726003AbfADBG1 (ORCPT ); Thu, 3 Jan 2019 20:06:27 -0500 Received: from localhost (dcvr.yhbt.net [127.0.0.1]) by dcvr.yhbt.net (Postfix) with ESMTP id 8C4DF1F6A9; Fri, 4 Jan 2019 01:06:26 +0000 (UTC) Date: Fri, 4 Jan 2019 01:06:26 +0000 From: Eric Wong To: Joonas Lahtinen Cc: Daniel Vetter , David Airlie , David Woodhouse , Jani Nikula , Joerg Roedel , Rodrigo Vivi , iommu@lists.linux-foundation.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: iommu_intel or i915 regression in 4.18, 4.19.12 and drm-tip Message-ID: <20190104010626.e6yqdqkmdcqjepke@dcvr> References: <20181227114948.ev4b3jte3ubsc5us@dcvr> <154642214920.6261.102817444136744919@jlahtine-desk.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <154642214920.6261.102817444136744919@jlahtine-desk.ger.corp.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Joonas Lahtinen wrote: > Quoting Eric Wong (2018-12-27 13:49:48) > > I just got a used Thinkpad X201 (Core i5 M 520, Intel QM57 > > chipset) and hit some kernel panics while trying to view > > image/animation-intensive stuff in Firefox (X11) unless I use > > "iommu_intel=igfx_off". > > > > With Debian stable backport kernels, "linux-image-4.17.0-0.bpo.3-amd64" > > (4.17.17-1~bpo9+1) has no problems. But "linux-image-4.18.0-0.bpo.3-amd64" > > (4.18.20-2~bpo9+1) gives a blank screen before I can login via agetty > > and run startx. > Most confusing about this is that 4.17 would have worked to begin with, > without intel_iommu=igfx_off (unless it was the default for older > kernel?) Yeah, so the Debian bpo 4.17(.17) kernel did not set CONFIG_INTEL_IOMMU_DEFAULT_ON, so I didn't encounter problems. My self-built kernels all set CONFIG_INTEL_IOMMU_DEFAULT_ON. Booting the Debian 4.17 kernel with "intel_iommu=on" gives the same hanging problem I hit with self-built 4.19.{12,13} kernels. I'm not sure how far back the problem goes (maybe forever), since I only got this hardware. Not sure what's the problem with Debian 4.18, either; but (self-built) 4.19.13 is fine w/o CONFIG_INTEL_IOMMU_DEFAULT_ON. Debian backports doesn't have kernels for 4.19 or 4.20, yet. > Did you maybe update other parts of the system while updating the > kernel? Definitely not; just the kernel + headers ("make bindeb-pkg)". > If you could attach full boot dmesg from working and non-working kernel + > have config file of both kernel's in Bugzilla. That'd be a good start! Sorry, I get anxiety attacks when it comes to logins and forms. Anyways, I managed to get the Debian kernel dmesg output uploaded with and without iommu_intel=on: https://bugs.freedesktop.org/attachment.cgi?bugid=109219