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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 EF868C43441 for ; Wed, 10 Oct 2018 08:07:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C021B20841 for ; Wed, 10 Oct 2018 08:07:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C021B20841 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=intra2net.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-pci-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726616AbeJJP2V (ORCPT ); Wed, 10 Oct 2018 11:28:21 -0400 Received: from rs07.intra2net.com ([85.214.138.66]:39332 "EHLO rs07.intra2net.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725837AbeJJP2V (ORCPT ); Wed, 10 Oct 2018 11:28:21 -0400 X-Greylist: delayed 421 seconds by postgrey-1.27 at vger.kernel.org; Wed, 10 Oct 2018 11:28:20 EDT Received: from mail.m.i2n (unknown [172.17.128.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by rs07.intra2net.com (Postfix) with ESMTPS id 7091A15000CA; Wed, 10 Oct 2018 10:00:20 +0200 (CEST) Received: from localhost (mail.m.i2n [127.0.0.1]) by localhost (Postfix) with ESMTP id 222412D9; Wed, 10 Oct 2018 10:00:20 +0200 (CEST) X-Virus-Scanned: by Intra2net Mail Security (AVE=8.3.52.82,VDF=8.15.8.188) Received: from storm.m.i2n (storm.m.i2n [172.16.1.2]) by mail.m.i2n (Postfix) with ESMTP id BEAD722E; Wed, 10 Oct 2018 10:00:13 +0200 (CEST) From: Thomas Jarosch To: Bjorn Helgaas Cc: Bin Meng , Bjorn Helgaas , linux-pci , stable , jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, rodrigo.vivi@intel.com, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel Subject: Re: [PATCH] pci: Add a few new IDs for Intel GPU "spurious interrupt" quirk Date: Wed, 10 Oct 2018 10:00:13 +0200 Message-ID: <5897590.Qva4cvS4Tx@storm.m.i2n> Organization: Intra2net AG In-Reply-To: <20181009170158.GA5906@bhelgaas-glaptop.roam.corp.google.com> References: <1537974841-29928-1-git-send-email-bmeng.cn@gmail.com> <20181009170158.GA5906@bhelgaas-glaptop.roam.corp.google.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Hello together, On Tuesday, 9 October 2018 19:01:58 CEST Bjorn Helgaas wrote: > > > Do you happen to know if Windows has the same problem? I.e., if you > > > boot an old version of Windows with a new GPU, and unplug the VGA > > > cable, does Windows crash? If Windows can figure out how to handle > > > that situation gracefully, Linux should be able to do it, too. > > > > I suspect Windows cannot handle it too. Without the GPU awareness, the > > interrupt line is simply on and no driver claims the devices and will > > cause issues. I can test this. > > If you could test this, that would be great. I would be quite > surprised if Windows crashed when you unplug the VGA cable. [original patch author from 2012 chiming in here] When doing a test on Windows, I guess it's vital to use a generic VGA / VESA driver. The Intel GPU driver will modify the interrupt configuration registers. Also at least I don't know if Windows has similar logic like Linux to disable spurious interrupts after XX unhandled interrupts. Personally I'm unsure if the Windows test is worth the time. Back in 2012 I tried to report this as a video BIOS bug via the Intel Open Source Technology Center. There was not much interest to report an issue to the BIOS developers. I have private emails from other people with similar problems on "Kenosha Pass" based boards. One of them talked to an actual Intel BIOS engineer in 2014, but still that didn't get anything fixed. Regarding a generic fix: The problem is testing on real hardware. Some Intel GPUs have different configuration registers. The Intel GPU driver could be used as template, but doing a fix without actual hardware to verify it is unsafe (=might mess up the system in unexpected ways). Related ideas from Daniel Vetter in 2014: https://lists.freedesktop.org/archives/intel-gfx/2014-August/050448.html Cheers, Thomas