Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752334AbbG3Pcg (ORCPT ); Thu, 30 Jul 2015 11:32:36 -0400 Received: from imap.thunk.org ([74.207.234.97]:59525 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751289AbbG3Pcd (ORCPT ); Thu, 30 Jul 2015 11:32:33 -0400 Date: Thu, 30 Jul 2015 11:32:28 -0400 From: "Theodore Ts'o" To: Linus Torvalds , intel-gfx , DRI , Daniel Vetter , Mani Nikula , Ander Conselvan de Oliveira , Linux Kernel Mailing List Subject: Re: [REGRESSION] Re: i915 driver crashes on T540p if docking station attached Message-ID: <20150730153228.GA15113@thunk.org> Mail-Followup-To: Theodore Ts'o , Linus Torvalds , intel-gfx , DRI , Daniel Vetter , Mani Nikula , Ander Conselvan de Oliveira , Linux Kernel Mailing List References: <20150730004937.GA3133@thunk.org> <20150730013912.GA4068@thunk.org> <20150730144002.GY16722@phenom.ffwll.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150730144002.GY16722@phenom.ffwll.local> User-Agent: Mutt/1.5.23 (2014-03-12) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2183 Lines: 47 On Thu, Jul 30, 2015 at 04:40:02PM +0200, Daniel Vetter wrote: > On Wed, Jul 29, 2015 at 10:18:16PM -0700, Linus Torvalds wrote: > > drivers/gpu/drm/drm_atomic_helper.c | 8 +++++--- > > 1 file changed, 5 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c > > index 5b59d5ad7d1c..aac212297b49 100644 > > --- a/drivers/gpu/drm/drm_atomic_helper.c > > +++ b/drivers/gpu/drm/drm_atomic_helper.c > > @@ -230,10 +230,12 @@ update_connector_routing(struct drm_atomic_state *state, int conn_idx) > > } > > > > connector_state->best_encoder = new_encoder; > > - idx = drm_crtc_index(connector_state->crtc); > > + if (connector_state->crtc) { > > + idx = drm_crtc_index(connector_state->crtc); > > > > - crtc_state = state->crtc_states[idx]; > > - crtc_state->mode_changed = true; > > + crtc_state = state->crtc_states[idx]; > > + crtc_state->mode_changed = true; > > + } > > This shouldn't happen since if it does we ended up stealing the encoder > from the connector itself (we do check for connector_state->crtc earlier) > and that would be a bug. I haven't figured out a precise theory but my > guess is on the best_encoder selection, and indeed dp mst encoder > selection seems to have gone belly up in 4.2 with the bisected commit. Well, I just tested Linus's patch and it works. BTW, is there any chance that I can suspend my laptop, and then move it from my docking station at home (where I have a Dell 30" display) to my docking station at work (where I have a Dell 24" display), and actually have the new monitor be detected? For at least the past year, I have to reboot in order to be able to use the external monitor? This used to work, but it's been a very long-standing regression. I undrstand that Multi-stream DP is a evil horrible hack, and supporting it is painful, but this used to work, and it hasn't in a long time. :-( - Ted -- 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/