From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2993146AbXCIVTb (ORCPT ); Fri, 9 Mar 2007 16:19:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2993145AbXCIVTb (ORCPT ); Fri, 9 Mar 2007 16:19:31 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:2214 "EHLO spitz.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2993144AbXCIVTa (ORCPT ); Fri, 9 Mar 2007 16:19:30 -0500 Date: Fri, 9 Mar 2007 21:19:10 +0000 From: Pavel Machek To: Andrew Johnson Cc: Matthew Garrett , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Software Suspend: Fix suspend when console is in VT_AUTO/KD_GRAPHICS mode Message-ID: <20070309211910.GD6374@ucw.cz> References: <1173394485.28589.17.camel@localhost.localdomain> <20070309090805.GA5822@atrey.karlin.mff.cuni.cz> <20070309153456.GA28664@srcf.ucam.org> <1173466942.29923.6.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1173466942.29923.6.camel@localhost.localdomain> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > > So... if current console is graphical, we leave X accessing the > > > console... That's bad, because video state is not going to be > > > restored...? > > > > A graphical console is not necessarily X. Is there any requirement for > > there to be a single VT that isn't in text mode? The vt switching is > > a hack, we shouldn't make life difficult for people who have their own > > userspace code that's entirely capable of restoring video state on its > > own. > > I realised that the previous patch would disallow a console switch while > running X. Attached is an updated patch with this scenario fixed. > > Another approach might be to fail in vt_waitactive() if a console switch > is not going to occur. > > -- Andrew > > > -void set_console(int nr) > +extern char vt_dont_switch; > + What does this variable do and why do we want to use it here? > +int set_console(int nr) > { > + struct vc_data *vc = vc_cons[fg_console].d; > + > + if(!vc_cons_allocated(nr) || vt_dont_switch || 'if (' > + (vc->vt_mode.mode != VT_PROCESS && vc->vc_mode == KD_GRAPHICS)) { > + > + return -EINVAL; > + } > + I assume you want ...mode == VT_AUTO here? And big comment explaining why we want this behaviour? And another big comment explaining why this will not break existing set_console() users? > want_console = nr; > schedule_console_callback(); > + > + return 0; > } > > struct tty_driver *console_driver; > diff -rup linux-2.6.20.1/drivers/char/vt_ioctl.c > linux/drivers/char/vt_ioctl.c > --- linux-2.6.20.1/drivers/char/vt_ioctl.c 2007-02-19 22:34:32.000000000 > -0800 > +++ linux/drivers/char/vt_ioctl.c 2007-03-08 14:15:41.000000000 -0800 > @@ -34,7 +34,7 @@ > #include > #include > > -static char vt_dont_switch; > +char vt_dont_switch; > extern struct tty_driver *console_driver; > > #define VT_IS_IN_USE(i) (console_driver->ttys[i] && > console_driver->ttys[i]->count) > diff -rup linux-2.6.20.1/include/linux/kbd_kern.h > linux/include/linux/kbd_kern.h > --- linux-2.6.20.1/include/linux/kbd_kern.h 2007-02-19 > 22:34:32.000000000 -0800 > +++ linux/include/linux/kbd_kern.h 2007-03-08 14:15:41.000000000 -0800 > @@ -75,7 +75,7 @@ extern int do_poke_blanked_console; > > extern void (*kbd_ledfunc)(unsigned int led); > > -extern void set_console(int nr); > +extern int set_console(int nr); > extern void schedule_console_callback(void); > > static inline void set_leds(void) > diff -rup linux-2.6.20.1/kernel/power/console.c > linux/kernel/power/console.c > --- linux-2.6.20.1/kernel/power/console.c 2007-02-19 22:34:32.000000000 > -0800 > +++ linux/kernel/power/console.c 2007-03-08 14:15:41.000000000 -0800 > @@ -27,7 +27,11 @@ int pm_prepare_console(void) > return 1; > } > > - set_console(SUSPEND_CONSOLE); > + if (set_console(SUSPEND_CONSOLE)) { > + /* Unable to change to the new console */ That's not what the comment should say. It should explain why it is okay to proceed when we can't change to text console. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html