From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751217AbWFFLKm (ORCPT ); Tue, 6 Jun 2006 07:10:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751226AbWFFLKm (ORCPT ); Tue, 6 Jun 2006 07:10:42 -0400 Received: from wx-out-0102.google.com ([66.249.82.198]:53140 "EHLO wx-out-0102.google.com") by vger.kernel.org with ESMTP id S1751217AbWFFLKc (ORCPT ); Tue, 6 Jun 2006 07:10:32 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:user-agent:mime-version:to:cc:subject:content-type:content-transfer-encoding; b=L5CtV6ZxTbJdF515hjVL1GX8jlYPJB/JEspw+AaRZjU8ZD/alt2WdqPDt6au9DaaIYG3LEjUCgvLdtqZgD+A+Y3htCzst8Mk2m7piIkbMM/SV7nEAXmS6oJcA438F0V0DYIXFQkyS1IFh3ZQz1HrWAwxvwuTaYiNzdMmCJzxwNA= Message-ID: <44856232.8090909@gmail.com> Date: Tue, 06 Jun 2006 19:08:34 +0800 From: "Antonino A. Daplas" User-Agent: Thunderbird 1.5.0.4 (X11/20060516) MIME-Version: 1.0 To: Andrew Morton CC: Linux Fbdev development list , Linux Kernel Development Subject: [PATCH 2/7] Detaching fbcon: Fix give_up_console() Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org To allow for detaching fbcon, it must be able to give up the console. However, the function give_up_console() is plain broken. It just sets the entries in the console driver map to NULL, it leaves the vt layer without a console driver, and does not decrement the module reference count. Calling give_up_console() is guaranteed to hang the machine.. To fix this problem, ensure that the virtual consoles are not left dangling without a driver. All systems have a default boot driver (either vgacon or dummycon) which is never unloaded. For those vt's that lost their driver, the default boot driver is reassigned back to them. Signed-off-by: Antonino Daplas --- drivers/char/vt.c | 29 +++++++++++++++++++++-------- 1 files changed, 21 insertions(+), 8 deletions(-) diff --git a/drivers/char/vt.c b/drivers/char/vt.c index eb27eed..d7ff7fd 100644 --- a/drivers/char/vt.c +++ b/drivers/char/vt.c @@ -100,6 +100,7 @@ #include const struct consw *conswitchp; +static struct consw *defcsw; /* default console */ /* A bitmap for codes <32. A bit of 1 indicates that the code * corresponding to that bit number invokes some special action @@ -2673,17 +2674,23 @@ int take_over_console(const struct consw if (!try_module_get(owner)) return -ENODEV; - acquire_console_sem(); + /* save default console, for possible recovery later on */ + if (!defcsw) + defcsw = (struct consw *) conswitchp; + acquire_console_sem(); desc = csw->con_startup(); + if (!desc) { release_console_sem(); module_put(owner); return -ENODEV; } + if (deflt) { if (conswitchp) module_put(conswitchp->owner); + __module_get(owner); conswitchp = csw; } @@ -2701,6 +2708,7 @@ int take_over_console(const struct consw continue; j = i; + if (CON_IS_VISIBLE(vc)) { k = i; save_screen(vc); @@ -2709,10 +2717,8 @@ int take_over_console(const struct consw old_was_color = vc->vc_can_do_color; vc->vc_sw->con_deinit(vc); vc->vc_origin = (unsigned long)vc->vc_screenbuf; - vc->vc_visible_origin = vc->vc_origin; - vc->vc_scr_end = vc->vc_origin + vc->vc_screenbuf_size; - vc->vc_pos = vc->vc_origin + vc->vc_size_row * vc->vc_y + 2 * vc->vc_x; visual_init(vc, i, 0); + set_origin(vc); update_attr(vc); /* If the console changed between mono <-> color, then @@ -2741,22 +2747,29 @@ int take_over_console(const struct consw printk("to %s\n", desc); release_console_sem(); - module_put(owner); return 0; } void give_up_console(const struct consw *csw) { - int i; + int i, first = -1, last = -1, deflt = 0; - for(i = 0; i < MAX_NR_CONSOLES; i++) + for (i = 0; i < MAX_NR_CONSOLES; i++) if (con_driver_map[i] == csw) { + if (first == -1) + first = i; + last = i; module_put(csw->owner); con_driver_map[i] = NULL; } -} + if (first != -1 && defcsw) { + if (first == 0 && last == MAX_NR_CONSOLES - 1) + deflt = 1; + take_over_console(defcsw, first, last, deflt); + } +} #endif /*