From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752261AbaEMQsf (ORCPT ); Tue, 13 May 2014 12:48:35 -0400 Received: from mail-wg0-f45.google.com ([74.125.82.45]:64312 "EHLO mail-wg0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751689AbaEMQs1 (ORCPT ); Tue, 13 May 2014 12:48:27 -0400 Date: Tue, 13 May 2014 18:48:20 +0200 From: Daniel Vetter To: Damien Lespiau Cc: =?iso-8859-1?Q?J=F6rg?= Otte , Ville =?iso-8859-1?Q?Syrj=E4l=E4?= , David Airlie , intel-gfx , Linux Kernel Mailing List , Dave Airlie , Linus Torvalds Subject: Re: [Intel-gfx] [3.14.0-rc4] regression: drm FIFO underruns Message-ID: <20140513164820.GQ3908@phenom.ffwll.local> Mail-Followup-To: Damien Lespiau , =?iso-8859-1?Q?J=F6rg?= Otte , Ville =?iso-8859-1?Q?Syrj=E4l=E4?= , David Airlie , intel-gfx , Linux Kernel Mailing List , Dave Airlie , Linus Torvalds References: <20140512190300.GF25056@phenom.ffwll.local> <20140513132200.GC3908@phenom.ffwll.local> <20140513163832.GM3908@phenom.ffwll.local> <20140513164631.GA16632@strange.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140513164631.GA16632@strange.amr.corp.intel.com> X-Operating-System: Linux phenom 3.14.0+ User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 13, 2014 at 05:46:31PM +0100, Damien Lespiau wrote: > On Tue, May 13, 2014 at 06:38:32PM +0200, Daniel Vetter wrote: > > > Doesn't work for me, I still have an underrun at boot-up. > > > > I'm at a loss tbh with ideas. We successfully disable both pipes, then > > enable pipe A and it all works. > > > > Then we enable pipe B and _both_ pipes underrun immediately afterwards. > > Really strange. Can you please reproduce the issue again on > > drm-intel-nightly (latest -nightly should also have the display > > corruptions fixed, so good to retest anyway) and attach a new dmesg with > > drm.debug=0xe. > > > > Meanwhile I'll try to come up with new theories and ideas. > > I do remember a reporter saying a BIOS upgrade fixed that for him. This > is one of the reasons Paulo put that BIOS update message. > > It's worth the try if you ask me (the BIOS update will bring new memory > latency values). The fifo underrun code should be able to cope with bios stupidity - that's why we don't enable it on takeover. Apparently there's a bug in that logic somewhere. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch