Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933483Ab0G3Sti (ORCPT ); Fri, 30 Jul 2010 14:49:38 -0400 Received: from kroah.org ([198.145.64.141]:35726 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932256Ab0G3Rej (ORCPT ); Fri, 30 Jul 2010 13:34:39 -0400 X-Mailbox-Line: From gregkh@clark.site Fri Jul 30 10:31:07 2010 Message-Id: <20100730173107.230441672@clark.site> User-Agent: quilt/0.48-11.2 Date: Fri, 30 Jul 2010 10:30:15 -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, Dave Airlie Subject: [050/140] drm/i915: enable low power render writes on GEN3 hardware. In-Reply-To: <20100730173205.GA22581@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1893 Lines: 59 2.6.33-stable review patch. If anyone has any objections, please let us know. ------------------ From: Dave Airlie commit 944001201ca0196bcdb088129e5866a9f379d08c upstream. A lot of 945GMs have had stability issues for a long time, this manifested as X hangs, blitter engine hangs, and lots of crashes. one such report is at: https://bugs.freedesktop.org/show_bug.cgi?id=20560 along with numerous distro bugzillas. This only took a week of digging and hair ripping to figure out. Tracked down and tested on a 945GM Lenovo T60, previously running x11perf -copypixwin500 or x11perf -copywinpix500 repeatedly would cause the GPU to wedge within 4 or 5 tries, with random busy bits set. After this patch no hangs were observed. Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/i915_gem.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -4999,6 +4999,16 @@ i915_gem_load(struct drm_device *dev) list_add(&dev_priv->mm.shrink_list, &shrink_list); spin_unlock(&shrink_list_lock); + /* On GEN3 we really need to make sure the ARB C3 LP bit is set */ + if (IS_GEN3(dev)) { + u32 tmp = I915_READ(MI_ARB_STATE); + if (!(tmp & MI_ARB_C3_LP_WRITE_ENABLE)) { + /* arb state is a masked write, so set bit + bit in mask */ + tmp = MI_ARB_C3_LP_WRITE_ENABLE | (MI_ARB_C3_LP_WRITE_ENABLE << MI_ARB_MASK_SHIFT); + I915_WRITE(MI_ARB_STATE, tmp); + } + } + /* Old X drivers will take 0-2 for front, back, depth buffers */ dev_priv->fence_reg_start = 3; -- 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/