From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sascha Hauer Date: Wed, 27 Jun 2012 16:22:38 +0000 Subject: Re: [PATCH, RFC] displaymodes in devicetree Message-Id: <20120627162238.GS1623@pengutronix.de> List-Id: References: <20120627124313.GI1623@pengutronix.de> <4FEB31CC.2060705@firmworks.com> In-Reply-To: <4FEB31CC.2060705-D5eQfiDGL7eakBO8gow8eQ@public.gmane.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Mitch Bradley Cc: kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, Laurent Pinchart On Wed, Jun 27, 2012 at 06:16:12AM -1000, Mitch Bradley wrote: > On 6/27/2012 2:43 AM, Sascha Hauer wrote: > >Hi All, > > > >I'd like to have a possibility to describe fixed display modes in the > >devicetree. This topic has been discussed before here: > > > >https://lists.ozlabs.org/pipermail/linuxppc-dev/2010-February/080683.html > > > >The result at that time was that EDID data should be considered to use > >as this is a format that already exists. I want to come back to this > >topic since: > > > >- EDID data is a binary format and as such quite inconvenient to handle. > > There exist several tools to parse EDID data, but I'm not aware of any > > (open source) tool which can generate EDID data. > >- EDID blobs are hard to modify and hard to review in patches. > >- EDID is designed to describe multiple modes, but fixed displays > > usually only support a single fixed mode. > > > >There are several ways of describing the mode, for this patch I chose to > >use the format (and naming) used by the Linux Framebuffer Layer as this > >is the only description which does not allow for inconsistent modes. I > >added the most common flags like [v|h]sync_active_high. Others can be > >added, but these flags are pretty much agreed upon and won't be > >superseeded with other flags. The mode from the devicetree can be > >converted to the most common modes used in Linux, struct fb_videomode > >and struct drm_display_mode. > > > >Comments welcome > > > I like the general approach and the set of names. The separators > inside the names should be hyphen (-) not underscore (_), following > the usual device tree convention. The rationale for that convention > is to follow natural-language usage, not the identifier constraints > of programming languages based on algebraic expressions. Good to hear that this is the convention for devicetree, I like hyphens better aswell. Will change. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |