Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754194AbaGHIfD (ORCPT ); Tue, 8 Jul 2014 04:35:03 -0400 Received: from mail-wi0-f178.google.com ([209.85.212.178]:60599 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753576AbaGHIez (ORCPT ); Tue, 8 Jul 2014 04:34:55 -0400 Date: Tue, 8 Jul 2014 10:35:05 +0200 From: Daniel Vetter To: Jiri Kosina Cc: Chris Wilson , Pavel Machek , "intel-gfx@lists.freedesktop.org" , Linus Torvalds , Linux Kernel Mailing List , Thomas Meyer Subject: Re: [Intel-gfx] Linux 3.16-rc2 Message-ID: <20140708083505.GQ17271@phenom.ffwll.local> Mail-Followup-To: Jiri Kosina , Chris Wilson , Pavel Machek , "intel-gfx@lists.freedesktop.org" , Linus Torvalds , Linux Kernel Mailing List , Thomas Meyer References: <871tuea7nz.fsf@intel.com> <20140624115753.GD17674@nuc-i3427.alporthouse.com> <1403612670.3091.10.camel@localhost.localdomain> <20140624122737.GF17674@nuc-i3427.alporthouse.com> <20140630100220.GA4934@xo-6d-61-c0.localdomain> <20140630100925.GA18836@nuc-i3427.alporthouse.com> <1404317921.3910.3.camel@localhost.localdomain> <20140707151613.GG5821@phenom.ffwll.local> <20140707160402.GA26405@nuc-i3427.alporthouse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: Linux phenom 3.15.0-rc3+ 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, Jul 08, 2014 at 12:15:31AM +0200, Jiri Kosina wrote: > On Mon, 7 Jul 2014, Chris Wilson wrote: > > > > > this patch on top of v3.16-rc3-62-gd92a333 makes the resume from ram > > > > regression go away on my machine: > > > > > > Hm, we could conditionalize this hack on IS_G4X ... Chris, thoughts? > > > > As different machines favour different w/a, I think the issue is mostly > > timing related. It could be sequence of register writes, but we tried > > different orders early on. The next experiment I guess would be to > > insert small delays between each write to see if that helps. Or to write > > each register twice. > > I actually tried to introduce rather large delays between individual > I915_WRITE() calls in the ring initialization sequence a couple weeks ago > already, but it resulted in complete machine lockup (which is worse than > my usual symptoms) during resume. Therefore I probably lack the knowledge > of internal workings of the HW that would allow me to guess what the > reasonable timeout value should be. Have you used msleep or udelay? The latter just spins the cpu and might be less dangerous. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/