From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1033210AbdAJMpF (ORCPT ); Tue, 10 Jan 2017 07:45:05 -0500 Received: from mx2.suse.de ([195.135.220.15]:37597 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752323AbdAJMpD (ORCPT ); Tue, 10 Jan 2017 07:45:03 -0500 Date: Tue, 10 Jan 2017 13:45:01 +0100 Message-ID: From: Takashi Iwai To: Daniel Vetter Cc: Ville =?UTF-8?B?U3lyasOkbMOk?= , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH] drm: Fix broken VT switch with video=1366x768 option In-Reply-To: <20170110124142.yosrvqsln4q6dm4h@phenom.ffwll.local> References: <20170109145614.29454-1-tiwai@suse.de> <20170110112836.GZ31595@intel.com> <20170110124142.yosrvqsln4q6dm4h@phenom.ffwll.local> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.1 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 10 Jan 2017 13:41:42 +0100, Daniel Vetter wrote: > > On Tue, Jan 10, 2017 at 12:36:50PM +0100, Takashi Iwai wrote: > > On Tue, 10 Jan 2017 12:28:36 +0100, > > Ville Syrjälä wrote: > > > > > > On Mon, Jan 09, 2017 at 03:56:14PM +0100, Takashi Iwai wrote: > > > > I noticed that the VT switch doesn't work any longer with a Dell > > > > laptop with 1366x768 eDP when the machine is connected with a DP > > > > monitor. It behaves as if VT were switched, but the graphics remain > > > > frozen. Actually the keyboard works, so I could switch back to VT7 > > > > again. > > > > > > > > I tried to track down the problem, and encountered a long story until > > > > we reach to this error: > > > > > > > > - The machine is booted with video=1366x768 option (the distro > > > > installer seems to add it as default). > > > > - Recently, drm_helper_probe_single_connector_modes() deals with > > > > cmdline modes, and it tries to create a new mode when no > > > > matching mode is found. > > > > - The drm_mode_create_from_cmdline_mode() creates a mode based on > > > > either CVT of GFT according to the given cmdline mode; in our case, > > > > it's 1366x768. > > > > - Since both CVT and GFT can't express the width 1366 due to > > > > alignment, the resultant mode becomes 1368x768, slightly larger than > > > > the given size. > > > > - Later on, the atomic commit is performed, and in > > > > drm_atomic_check_only(), the size of each plane is checked. > > > > - The size check of 1366x768 fails due to the above, and eventually > > > > the whole VT switch fails. > > > > > > > > Back in the history, we've had a manual fix-up of 1368x768 in various > > > > places via c09dedb7a50e ("drm/edid: Add a workaround for 1366x768 HD > > > > panel"), but they have been all in drm_edid.c at probing the modes > > > > from EDID. For addressing the problem above, we need a similar hack > > > > to the mode newly created from cmdline, manually adjusting the width > > > > when the expected size is 1366 while we get 1368 instead. > > > > > > > > Fixes: eaf99c749d43 ("drm: Perform cmdline mode parsing during...") > > > > Cc: > > > > Signed-off-by: Takashi Iwai > > > > --- > > > > drivers/gpu/drm/drm_modes.c | 7 +++++++ > > > > 1 file changed, 7 insertions(+) > > > > > > > > diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c > > > > index ac6a35212501..e6b19bc9021a 100644 > > > > --- a/drivers/gpu/drm/drm_modes.c > > > > +++ b/drivers/gpu/drm/drm_modes.c > > > > @@ -1460,6 +1460,13 @@ drm_mode_create_from_cmdline_mode(struct drm_device *dev, > > > > return NULL; > > > > > > > > mode->type |= DRM_MODE_TYPE_USERDEF; > > > > + /* fix up 1368x768: GFT/CVT can't express 1366 width due to alignment */ > > > > + if (cmd->xres == 1366 && mode->hdisplay == 1368) { > > > > + mode->hdisplay = 1366; > > > > + mode->hsync_start--; > > > > + mode->hsync_end--; > > > > + drm_mode_set_name(mode); > > > > + } > > > > > > Maybe give fixup_mode_1366x768() a drm_ prefix and make in non-static to > > > avoid duplicating the code? And I guess move it to drm_modes.c? > > > > Yes, that'll be a good cleanup. I was afraid of symbol export, but > > both are in the same module, so far. I can post a follow-up once when > > this one gets accepted. > > For the follow up, pls put the decl into drm_crtc_internal.h, so that > drivers aren't tempted to use it. That header is for module-internal > shared code only. Alright, thanks for information. Takashi