From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A426C38A2D for ; Tue, 25 Oct 2022 20:32:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232821AbiJYUc3 (ORCPT ); Tue, 25 Oct 2022 16:32:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52588 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231772AbiJYUc1 (ORCPT ); Tue, 25 Oct 2022 16:32:27 -0400 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 81016ABD61 for ; Tue, 25 Oct 2022 13:32:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1666729946; x=1698265946; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=GVo3VBqPRovcZf5EP7+TCdOX+BecorKE93akHNypg2U=; b=FK7LisxKk/gelIL1ifi3OeGvtlNyyFbtB3261O3Zo1hpYskRmJLowqxw wrixikr3Df+ki+HCZU7rJvvXmtwyOjGhJlIcpW5JN8ttrx+JtlN9gBw95 71rS3BWYrwq7PVB18exWIpO9JFhyp7P2hzdR1kUpvu2jtFpaMigSta05z SUDkZQhQTN4206apKh7E6J5xiAzl/kmePD+SyyMaKOX2+K9yo9A6MZr7e mThErKJ3oB9O7Mbo4OVcXz6ib9HumDuZ6lfgKy6w+Om5kVzLaEMbWDl41 aFY4fLLo5Fb2Ghi6iqT2fgwt9S3t65LfFB+jN0WS8XtKHUju7WSEh/PDp g==; X-IronPort-AV: E=McAfee;i="6500,9779,10511"; a="306515263" X-IronPort-AV: E=Sophos;i="5.95,212,1661842800"; d="scan'208";a="306515263" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Oct 2022 13:32:26 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10511"; a="774335851" X-IronPort-AV: E=Sophos;i="5.95,212,1661842800"; d="scan'208";a="774335851" Received: from stinkpipe.fi.intel.com (HELO stinkbox) ([10.237.72.191]) by fmsmga001.fm.intel.com with SMTP; 25 Oct 2022 13:32:24 -0700 Received: by stinkbox (sSMTP sendmail emulation); Tue, 25 Oct 2022 23:32:23 +0300 Date: Tue, 25 Oct 2022 23:32:23 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Jani Nikula Cc: intel-gfx@lists.freedesktop.org, stable@vger.kernel.org Subject: Re: [Intel-gfx] [PATCH] drm/i915/sdvo: Fallback to current output timings for LVDS fixed mode Message-ID: References: <20221025165938.17264-1-ville.syrjala@linux.intel.com> <878rl3eqx7.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <878rl3eqx7.fsf@intel.com> X-Patchwork-Hint: comment Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Tue, Oct 25, 2022 at 08:47:32PM +0300, Jani Nikula wrote: > On Tue, 25 Oct 2022, Ville Syrjala wrote: > > From: Ville Syrjälä > > > > If we can't dig out a fixed mode for LVDS from the VBT or EDID > > let's fall back to using the current output timings. This should > > work as long as the BIOS has (somehow) enabled the output. > > > > In this case we are dealing with the some kind of BLB based POS > > machine (Toshiba SurePOS 500) where neither the OpRegion mailbox > > nor the vbios ROM contain a valid VBT. And no EDID anywhere we > > could find either. > > > > Cc: # v5.19+ > > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/7301 > > Signed-off-by: Ville Syrjälä > > Reviewed-by: Jani Nikula > > But they're saying it's a regression between 4.19 and 5.10... Yeah. I can't actually figure out how it could have worked even with 4.19. Hmm. Actually now that I look at some of the hints in the logs it does look like it maybe did find an EDID after all. What confused me was that all the modes very much like the _noedid stuff. Ah, it looks like we fail to fully initialize the DDC stuff before setting up the outputs, which I guess explains why the EDID read fails there. Previously there was this funky feedback loop in that .get_modes() actually filled in the fixed_mode, so until you called that (after everything else was fully set up) you didn't have a fixed mode. And while looking at this stuff more I can see that the whole multi output support is still very much snafu :/ I'll see if I can make a fairly minimal fix for now... -- Ville Syrjälä Intel