From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S939097AbdEXIpC (ORCPT ); Wed, 24 May 2017 04:45:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:38660 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S939081AbdEXIo5 (ORCPT ); Wed, 24 May 2017 04:44:57 -0400 Date: Wed, 24 May 2017 10:44:50 +0200 From: Joerg Roedel To: "Deucher, Alexander" Cc: "'David Woodhouse'" , "'Joerg Roedel'" , Bjorn Helgaas , "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Daniel Drake , Samuel Sieb Subject: Re: [PATCH v2] PCI: Add ATS-disable quirk for AMD Stoney GPUs Message-ID: <20170524084450.GB12353@suse.de> References: <1491575538-22694-1-git-send-email-joro@8bytes.org> <1493893297.4904.71.camel@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Alexander, On Tue, May 23, 2017 at 07:54:12PM +0000, Deucher, Alexander wrote: > I finally got an answer from the hw team and we validated ATS on > stoney as well so in theory this patch shouldn’t actually be needed. > I think we may actually be papering over some other issue. The > following patch seems to also fix this issue (and other issues): > https://www.spinics.net/lists/stable/msg172631.html Yeah, but it still looks to me like that the hardware got into some weird state with the storm of ATS invalidations sent to it. The Completion-Wait loop timeouts seen in the original bug report indicate that the IOMMU is waiting for a response that never comes. And this is probably the ATS flush completion response from the GPU, as disabling ATS on the GPU makes the issue disappear. Regards, Joerg