From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755285AbbCBVD7 (ORCPT ); Mon, 2 Mar 2015 16:03:59 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:58154 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755104AbbCBVDy (ORCPT ); Mon, 2 Mar 2015 16:03:54 -0500 Date: Mon, 2 Mar 2015 22:03:49 +0100 From: Pavel Machek To: NeilBrown Cc: Tomi Valkeinen , linux-omap@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, GTA04 owners , "Rafael J. Wysocki" Subject: Re: [PATCH] OMAP: DSS: DPI: disable vt-switch on suspend/resume. Message-ID: <20150302210349.GE13270@amd> References: <20150225203708.0eb2fa96@notabene.brown> <54ED9DF8.8030105@ti.com> <20150226092646.7e20df30@notabene.brown> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150226092646.7e20df30@notabene.brown> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > Looking at the drivers/tty/vt/vt_ioctl.c, it sounds to me that we should > > always do pm_set_vt_switch(0), as omapdss restores everything just fine > > on resume. Although it makes me wonder how it works if there are two > > display controllers, one needing the switch and the other not... > > I wondered that too. It would seem to make more sense for > pm_set_vt_switch(0) to be the default, that drivers which need the textmode > switch should call (1). But I suspect there are "historical reasons" for the > current situation. Well... historically, we did not have drivers for graphics cards -- kernel did not know how to handle it, only X knew. For cards that do not have kernel driver, only X one, we need to switch vts. For cards that have proper driver, we should be able to survive without VT switch. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html