Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934941AbZLQBWN (ORCPT ); Wed, 16 Dec 2009 20:22:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763725AbZLQBVL (ORCPT ); Wed, 16 Dec 2009 20:21:11 -0500 Received: from kroah.org ([198.145.64.141]:41464 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763662AbZLQBU6 (ORCPT ); Wed, 16 Dec 2009 20:20:58 -0500 X-Mailbox-Line: From gregkh@mini.kroah.org Wed Dec 16 17:16:08 2009 Message-Id: <20091217011607.913966145@mini.kroah.org> User-Agent: quilt/0.48-1 Date: Wed, 16 Dec 2009 17:15:27 -0800 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, Chris Wilson , David Woodhouse , Zhenyu Wang , Zhenyu Wang , Eric Anholt Subject: [76/90] drm/i915: Avoid NULL dereference with component_only tv_modes In-Reply-To: <20091217011835.GA20434@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2012 Lines: 58 2.6.31-stable review patch. If anyone has any objections, please let us know. ------------------ From: Chris Wilson commit d271817baecbccb47da0d9f28c285a0dae8a06b7 upstream. In commit d2d9f2324, the guard for a valid video mode was removed. This caused the regression: kernel crash during kms graphic boot on Intel GM4500 platform https://bugzilla.redhat.com/show_bug.cgi?id=540218 This patches changes the logic slightly not to rely on a coupled variable, but to just check whether the video_modes is valid before dereferencing. Signed-off-by: Chris Wilson Cc: David Woodhouse Cc: Zhenyu Wang [ickle: Actually reference the correct bug report] Acked-by: Zhenyu Wang Signed-off-by: Eric Anholt Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/intel_tv.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) --- a/drivers/gpu/drm/i915/intel_tv.c +++ b/drivers/gpu/drm/i915/intel_tv.c @@ -1212,20 +1212,17 @@ intel_tv_mode_set(struct drm_encoder *en tv_ctl |= TV_TRILEVEL_SYNC; if (tv_mode->pal_burst) tv_ctl |= TV_PAL_BURST; + scctl1 = 0; - /* dda1 implies valid video levels */ - if (tv_mode->dda1_inc) { + if (tv_mode->dda1_inc) scctl1 |= TV_SC_DDA1_EN; - } - if (tv_mode->dda2_inc) scctl1 |= TV_SC_DDA2_EN; - if (tv_mode->dda3_inc) scctl1 |= TV_SC_DDA3_EN; - scctl1 |= tv_mode->sc_reset; - scctl1 |= video_levels->burst << TV_BURST_LEVEL_SHIFT; + if (video_levels) + scctl1 |= video_levels->burst << TV_BURST_LEVEL_SHIFT; scctl1 |= tv_mode->dda1_inc << TV_SCDDA1_INC_SHIFT; scctl2 = tv_mode->dda2_size << TV_SCDDA2_SIZE_SHIFT | -- 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/