Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756683AbaFWR45 (ORCPT ); Mon, 23 Jun 2014 13:56:57 -0400 Received: from mail-vc0-f170.google.com ([209.85.220.170]:37863 "EHLO mail-vc0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756541AbaFWR4z (ORCPT ); Mon, 23 Jun 2014 13:56:55 -0400 MIME-Version: 1.0 In-Reply-To: <1403539186.3804.46.camel@hornet> References: <1403018494-10264-1-git-send-email-pawel.moll@arm.com> <20140620170901.GA12059@leverpostej> <1403532837.3804.29.camel@hornet> <1403539186.3804.46.camel@hornet> From: Rob Herring Date: Mon, 23 Jun 2014 12:56:34 -0500 Message-ID: Subject: Re: [PATCH v7 1/2] video: ARM CLCD: Add DT support To: Pawel Moll Cc: Mark Rutland , Rob Herring , Ian Campbell , Kumar Gala , Jean-Christophe Plagniol-Villard , Tomi Valkeinen , Russell King , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-fbdev@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 23, 2014 at 10:59 AM, Pawel Moll wrote: > On Mon, 2014-06-23 at 16:43 +0100, Rob Herring wrote: >> On Mon, Jun 23, 2014 at 9:13 AM, Pawel Moll wrote: >> > On Fri, 2014-06-20 at 18:09 +0100, Mark Rutland wrote: >> >> > +- max-memory-bandwidth: maximum bandwidth in bytes per second that the >> >> > + cell's memory interface can handle >> >> >> >> When should I set this, given it is optional? >> > >> > When there is a (significant) limitation of the bandwidth available for >> > the cell's memory interface. One will either be told by the soc guys or >> > will figure it out in the hard way, as we did :-( >> >> What are you going to do with this information? b/w is a function of >> screen size and pixel depth. Are you going to refuse certain configs >> based on that? Seems like someone doing their own modes should know >> what they are doing and the limitations. >> >> Again, drop it until there is a defined need for this. > > Yes, there is. Use case: PL111 is wired up to a HDMI formatter, which > will take everything up to 1080p. This is what a DRM driver (what/if > it's ready) will get from the encoder driver (and rightly so). But the > chip interconnect limitations is make the chip being able to get 480p at > 60Hz tops. > > Or do you want me to add a subnode with timings for all achievable modes > instead? I want this solved in a generic way and not something pl111 specific. If this is already defined then use it. If not, I would drop this for now and get a pl111 binding in place finally. Rob -- 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/