Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754906AbbFQXbN (ORCPT ); Wed, 17 Jun 2015 19:31:13 -0400 Received: from pandora.arm.linux.org.uk ([78.32.30.218]:38562 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752997AbbFQXbJ (ORCPT ); Wed, 17 Jun 2015 19:31:09 -0400 Date: Thu, 18 Jun 2015 00:30:40 +0100 From: Russell King - ARM Linux To: Doug Anderson Cc: Philipp Zabel , Thierry Reding , Heiko Stuebner , David Airlie , Andy Yan , Yakir Yang , Fabio Estevam , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm: bridge/dw_hdmi: Filter modes > 165MHz for DVI Message-ID: <20150617233040.GE7557@n2100.arm.linux.org.uk> References: <1434582847-713-1-git-send-email-dianders@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1434582847-713-1-git-send-email-dianders@chromium.org> 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 Content-Length: 2018 Lines: 46 On Wed, Jun 17, 2015 at 04:14:07PM -0700, Doug Anderson wrote: > If you plug in a DVI monitor to your HDMI port, you need to filter out > clocks > 165MHz. That's because 165MHz is the maximum clock rate that > we can run single-link DVI at. > > If you want to run high resolutions to DVI, you'd need some type of an > active adapter that pretended that it was HDMI, interpreted the > signal, and produced a new dual link DVI signal at a lower clock rate. > > Signed-off-by: Doug Anderson > --- > Note: this patch was tested against a 3.14 kernel with backports. It > was only compile tested against linuxnext, but the code is > sufficiently similar that I'm convinced it will work there. Really? I have to wonder what your testing was... hdmi->vic = drm_match_cea_mode(mode); if (!hdmi->vic) { dev_dbg(hdmi->dev, "Non-CEA mode used in HDMI\n"); hdmi->hdmi_data.video_mode.mdvi = true; } else { dev_dbg(hdmi->dev, "CEA mode used vic=%d\n", hdmi->vic); hdmi->hdmi_data.video_mode.mdvi = false; } mdvi indicates whether the _currently set mode_ is a CEA mode or not (imho, it's mis-named). It doesn't indicate whether we have a HDMI display device or a DVI display device connected, which seems to be what you want to use it for below. To sort that, what you need to do is detect a HDMI display device using drm_detect_hdmi_monitor() on the EDID received from the device before parsing the modes, and save that value in a dw_hdmi struct member, and I'd suggest that it's a top-level struct member, not buried in 'hdmi_data' or 'video_mode'. -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net. -- 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/