Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751659AbbK1Ah5 (ORCPT ); Fri, 27 Nov 2015 19:37:57 -0500 Received: from mail-ig0-f181.google.com ([209.85.213.181]:37954 "EHLO mail-ig0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751428AbbK1Ahy (ORCPT ); Fri, 27 Nov 2015 19:37:54 -0500 MIME-Version: 1.0 In-Reply-To: References: <1448637005-3847-1-git-send-email-daniel.vetter@ffwll.ch> <1448637005-3847-2-git-send-email-daniel.vetter@ffwll.ch> Date: Fri, 27 Nov 2015 19:37:53 -0500 X-Google-Sender-Auth: NbkIfvrAkWgu6KAkyw08LuWiUb8 Message-ID: Subject: Re: [PATCH RESEND 2/2] drm/i915: prevent the vgacon from ever reloading From: Ilia Mirkin To: Emil Velikov Cc: Daniel Vetter , Andrew Morton , Greg Kroah-Hartman , Intel Graphics Development , LKML , DRI Development Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1921 Lines: 43 On Fri, Nov 27, 2015 at 10:40 AM, Emil Velikov wrote: > On 27 November 2015 at 15:10, Daniel Vetter wrote: >> It only leads to bloodshed and tears - we don't bother to restore a >> working legacy vga hw setup. >> >> On haswell with the new dynamic power well code this leads to even >> more hilarity since for some configurations the hardware is simply no >> longer there. >> >> The actual implementation is a bit a hack - we realy on fbcon to kick >> out the vgacon. To make this also work with I915_FBDEV=n (or FBCON=n) >> and VGA_CONSOLE=y i915 already unregisters the vga console manually >> early in the driver load sequence. >> > Interesting... nv50 and later GPUs are in a roughly similar shame > afaict. They lack the dedicated hardware and no one really bothered > figuring out how to restore things to a working shape [1]. > > Then again, upon sequential load of the nouveau module the GPU gets > initialised properly, where you can get X (weston?) up and running > without issues. Am I thinking about a different thing ? > > I take it that you guys do less of the (re)initialisation dance, to > ensure faster boot times ? > > Thanks, > Emil > > [1] http://nouveau.freedesktop.org/wiki/KernelModeSetting/#deactivatingkmsandunloadingnouveau FWIW it's possible to unload nouveau, at which point your screen turns off (because we can't restore the vga emulation junk... haven't the faintest clue how it works), and then reload it, at which point fbcon gets rebound and is completely happy. I can't tell what this patch is doing, but for your own sanity, you should support unloading/reloading i915 as well. -ilia -- 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/