Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751730AbbHQR40 (ORCPT ); Mon, 17 Aug 2015 13:56:26 -0400 Received: from gabe.freedesktop.org ([131.252.210.177]:58607 "EHLO gabe.freedesktop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750803AbbHQR4Z (ORCPT ); Mon, 17 Aug 2015 13:56:25 -0400 From: Eric Anholt To: Stephen Warren Cc: dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Lee Jones , devicetree@vger.kernel.org Subject: Re: [PATCH 3/7] drm/vc4: Add KMS support for Raspberry Pi. In-Reply-To: <55CEC3D8.7060103@wwwdotorg.org> References: <1439427380-2436-1-git-send-email-eric@anholt.net> <1439427380-2436-4-git-send-email-eric@anholt.net> <55CEC3D8.7060103@wwwdotorg.org> User-Agent: Notmuch/0.20.2 (http://notmuchmail.org) Emacs/24.5.1 (x86_64-pc-linux-gnu) Date: Mon, 17 Aug 2015 10:56:23 -0700 Message-ID: <877fotx0hk.fsf@eliezer.anholt.net> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1619 Lines: 38 r<#secure method=pgpmime mode=sign> Stephen Warren writes: > On 08/12/2015 06:56 PM, Eric Anholt wrote: >> This is the start of a full VC4 driver. Right now this just supports >> configuring the display using a pre-existing video mode (because >> changing the pixel clock isn't available yet, and doesn't work when it >> is). However, this is enough for fbcon and bringing up X using >> xf86-video-modesetting. > >> diff --git a/drivers/gpu/drm/vc4/Kconfig b/drivers/gpu/drm/vc4/Kconfig > >> +config DRM_VC4 >> + tristate "Broadcom VC4 Graphics" > >> + help >> + Choose this option if you have a system that has a Broadcom >> + VC4 GPU, such as the Raspberry Pi or other BCM2708/BCM2835. >> + >> + This driver requires that "avoid_warnings=2" be present in >> + the config.txt for the firmware, to keep it from smashing >> + our display setup. > > The need for "avoid_warnings=2" seems like it will trip people up. I > don't think it's in any config.txt I've seen. Can you expand more on that? The warnings thing is the firmware watching for undervoltage and then it calls into dispmanx to overlay a little rainbow box on the screen. This of course interferes with our display setup. I think we'll be able to wire up notifications to Linux for undervoltage, at which point we can do something useful with that information, ourselves. -- 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/