From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: [PATCH] video: hdmi: request underscan by default Date: Tue, 25 Feb 2014 12:33:21 +0200 Message-ID: <20140225103321.GV3852@intel.com> References: <1393280404-9066-1-git-send-email-drake@endlessm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTP id B8D1AFAD84 for ; Tue, 25 Feb 2014 02:33:25 -0800 (PST) Content-Disposition: inline In-Reply-To: <1393280404-9066-1-git-send-email-drake@endlessm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org To: Daniel Drake Cc: mjg59@srcf.ucam.org, treding@nvidia.com, dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org On Mon, Feb 24, 2014 at 04:20:04PM -0600, Daniel Drake wrote: > Working with HDMI TVs is a real pain as they tend to overscan by > default, meaning that the pixels around the edge of the framebuffer > are not displayed. This is well explained here: > http://mjg59.dreamwidth.org/8705.html > = > There is a bit in the HDMI info frame that can request that the > remote display shows the full pixel data ("underscan"). For the > remote display, the HDMI spec states that this is optional - it > doesn't have to listen. That means that most TVs will probably ignore > this. > = > But, maybe there are a handful of TVs for which this would help > the situation. As we live in a digital world, ask the remote > display not to overscan by default. > = > Signed-off-by: Daniel Drake Yeah, underscan would seem the saner default value. CEA-861 says that the source should always set the S bits appropriately if it knows what to put there, even if the sink claims that it won't respect those bits. So we're not violating the spec by doing this. I'm thinking we should also add a connector property to allow userspace to choose the scan behaviour. Or perhaps some driver already has such a property? I'm not sure we want to put this into hdmi.c though. Maybe better to avoid such policy in the infoframe code itself, and instead stick this into drm_hdmi_avi_infoframe_from_display_mode()? > --- > drivers/video/hdmi.c | 1 + > 1 file changed, 1 insertion(+) > = > diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c > index 9e758a8..6c2d924 100644 > --- a/drivers/video/hdmi.c > +++ b/drivers/video/hdmi.c > @@ -54,6 +54,7 @@ int hdmi_avi_infoframe_init(struct hdmi_avi_infoframe *= frame) > frame->type =3D HDMI_INFOFRAME_TYPE_AVI; > frame->version =3D 2; > frame->length =3D HDMI_AVI_INFOFRAME_SIZE; > + frame->scan_mode =3D HDMI_SCAN_MODE_UNDERSCAN; > = > return 0; > } > -- = > 1.8.3.2 > = > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel -- = Ville Syrj=E4l=E4 Intel OTC