From mboxrd@z Thu Jan 1 00:00:00 1970 From: Fabio Estevam Subject: Re: [PATCH] imx-drm: imx-hdmi: fix hdmi hotplug detection initial state Date: Mon, 9 Jun 2014 11:29:28 -0300 Message-ID: References: <20140609140639.GR23430@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ve0-f173.google.com (mail-ve0-f173.google.com [209.85.128.173]) by gabe.freedesktop.org (Postfix) with ESMTP id A535E6E5B1 for ; Mon, 9 Jun 2014 07:29:28 -0700 (PDT) Received: by mail-ve0-f173.google.com with SMTP id db11so1150599veb.4 for ; Mon, 09 Jun 2014 07:29:28 -0700 (PDT) In-Reply-To: <20140609140639.GR23430@n2100.arm.linux.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Russell King - ARM Linux Cc: devel@driverdev.osuosl.org, Greg Kroah-Hartman , DRI mailing list , Shawn Guo List-Id: dri-devel@lists.freedesktop.org On Mon, Jun 9, 2014 at 11:06 AM, Russell King - ARM Linux wrote: > Please check the status in /sys/class/drm/card0-HDMI-A-1/status. This > should report the current state of the hotplug detection. /sys/class/drm/card0-HDMI-A-1/status returns the correct state for HDMI cable connection. > Remember that this code detects off the HPD signal - if the HPD signal > has not been correctly wired up, this patch is not going to help (really > it comes down to a hardware fault, which I'm not trying to solve with > this patch.) > > What I'm trying to resolve with this patch is that the state detected > on properly wired up systems corresponds with the real initial state of > the interface at initialisation time. > > The problem with the current code is that we start off assuming that the > interface is disconnected, and we rely on an interrupt arriving to change > that state. If for whatever reason that interrupt does not arrive, then, > even if the HPD signal is active, we continue believing that the interface > is not connected. > > I seem to remember discussion in the past that the HPD signal is not > wired up on SabreSD. Really, this needs to be a DT flag to indicate It is sabrelite board that does not have HPD signal not wired up. sabresd does have HPD signal connected. The HDMI undetected issue I am seeing on sabresd seems to be related to the simultaneous usage of HDMI and LVDS. If I remove the ldb node from the imx6qdl-sabresd.dtsi, then the HDMI cable is correctly detected and HDMI is shown right after boot.