Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754949AbYJNXBS (ORCPT ); Tue, 14 Oct 2008 19:01:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751635AbYJNXBG (ORCPT ); Tue, 14 Oct 2008 19:01:06 -0400 Received: from cantor2.suse.de ([195.135.220.15]:37896 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751454AbYJNXBF (ORCPT ); Tue, 14 Oct 2008 19:01:05 -0400 Date: Tue, 14 Oct 2008 15:58:17 -0700 From: Brandon Philips To: Dave Airlie , Zhenyu Wang , Jesse Barnes Cc: linux-kernel@vger.kernel.org Subject: [PATCH] intel-agp: Avoid oops for G33 on 1MB stolen case Message-ID: <20081014225817.GA29267@plankton.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2468 Lines: 79 This is similar to f443675affe3f16dd428e46f0f7fd3f4d703eeab which was reverted because it broke older X.org driver. This patch only fixes the 1MB stolen case since it causes an oops. Xorg will not work without the accompanying patch[1] but avoiding an oops and making it possible to work with patched xorg driver is reasonable. [1] http://ifup.org/~philips/review/xf86-video-intel-G33-1mb.patch Explanation of the oops: > static void intel_i830_init_gtt_entries(void) ... > } else if (IS_G33) { > /* G33's GTT size defined in gmch_ctrl */ > switch (gmch_ctrl & G33_PGETBL_SIZE_MASK) { > case G33_PGETBL_SIZE_1M: > size = 1024; > break; ... > size += 4; size = 1028 Then since we have the BIOS setting 1MB for the device in the GMCH control we get to here: > } else { > switch (gmch_ctrl & I855_GMCH_GMS_MASK) { > case I855_GMCH_GMS_STOLEN_1M: > gtt_entries = MB(1) - KB(size); > break; MB(1) = 1 * 1024 * 1024 KB(1028) = 1028 * 1024 MB(1) - KB(1028) = -4096 > gtt_entries /= KB(4); > intel_private.gtt_entries = gtt_entries; We end up with -1 in gtt_entries. This leads to intel_i915_configure reading/writing to areas outside of mapped memory and the oops. Bugzilla: https://bugzilla.novell.com/show_bug.cgi?id=391261 Signed-off-by: Brandon Philips --- drivers/char/agp/intel-agp.c | 8 ++++++++ 1 file changed, 8 insertions(+) Index: linux-2.6/drivers/char/agp/intel-agp.c =================================================================== --- linux-2.6.orig/drivers/char/agp/intel-agp.c +++ linux-2.6/drivers/char/agp/intel-agp.c @@ -559,6 +559,14 @@ static void intel_i830_init_gtt_entries( } else { switch (gmch_ctrl & I855_GMCH_GMS_MASK) { case I855_GMCH_GMS_STOLEN_1M: + if (IS_G33) { + size = 0; + printk(KERN_WARNING PFX + "Warning: G33 chipset with 1MB" + " allocated. Older X.org Intel drivers" + " will not work.\n"); + WARN_ON(1); + } gtt_entries = MB(1) - KB(size); break; case I855_GMCH_GMS_STOLEN_4M: -- 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/