From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753995Ab1HNQHL (ORCPT ); Sun, 14 Aug 2011 12:07:11 -0400 Received: from cantor2.suse.de ([195.135.220.15]:36443 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752062Ab1HNQHG (ORCPT ); Sun, 14 Aug 2011 12:07:06 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Fri Aug 12 14:05:54 2011 Message-Id: <20110812210554.516350646@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Fri, 12 Aug 2011 14:04:12 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Keith Packard Subject: [27/90] drm/i915: Hold mode_config->mutex during hotplug processing In-Reply-To: <20110812210626.GA4725@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.0-stable review patch. If anyone has any objections, please let us know. ------------------ From: Keith Packard commit a65e34c79c88895766ab1f8a5afa451eed26622b upstream. Hotplug detection is a mode setting operation and must hold the struct_mutex or risk colliding with other mode setting operations. In particular, the display port hotplug function attempts to re-train the link if the monitor is supposed to be running when plugged back in. If that happens while mode setting is underway, the link will get scrambled, leaving it in an inconsistent state. This is a special case -- usually the driver mode setting entry points are covered by the upper level DRM code, but in this case the function is invoked as a work function not under the control of DRM. Signed-off-by: Keith Packard Reviewed-by: Jesse Barnes Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/i915_irq.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -306,6 +306,7 @@ static void i915_hotplug_work_func(struc struct drm_mode_config *mode_config = &dev->mode_config; struct intel_encoder *encoder; + mutex_lock(&mode_config->mutex); DRM_DEBUG_KMS("running encoder hotplug functions\n"); list_for_each_entry(encoder, &mode_config->encoder_list, base.head) @@ -314,6 +315,8 @@ static void i915_hotplug_work_func(struc /* Just fire off a uevent and let userspace tell us what to do */ drm_helper_hpd_irq_event(dev); + + mutex_unlock(&mode_config->mutex); } static void i915_handle_rps_change(struct drm_device *dev)