From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753875Ab1GHFBj (ORCPT ); Fri, 8 Jul 2011 01:01:39 -0400 Received: from cantor2.suse.de ([195.135.220.15]:41696 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753701Ab1GHFBg (ORCPT ); Fri, 8 Jul 2011 01:01:36 -0400 X-Mailbox-Line: From gregkh@clark.kroah.org Thu Jul 7 17:16:55 2011 Message-Id: <20110708001655.280182108@clark.kroah.org> User-Agent: quilt/0.48-16.4 Date: Thu, 07 Jul 2011 17:15:58 -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, Daniel J Blueman , Eric Anholt , Dave Airlie Subject: [026/107] drm/i915: Fix gen6 (SNB) missed BLT ring interrupts. In-Reply-To: <20110708001740.GA14031@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.39-stable review patch. If anyone has any objections, please let us know. ------------------ From: Daniel J Blueman commit 498e720b96379d8ee9c294950a01534a73defcf3 upstream. The failure appeared in dmesg as: [drm:i915_hangcheck_ring_idle] *ERROR* Hangcheck timer elapsed... blt ring idle [waiting on 35064155, at 35064155], missed IRQ? This works around that problem on by making the blitter command streamer write interrupt state to the Hardware Status Page when a MI_USER_INTERRUPT command is decoded, which appears to force the seqno out to memory before the interrupt happens. v1->v2: Moved to prior interrupt handler installation and RMW flags as per feedback. v2->v3: Removed RMW of flags (by anholt) Signed-off-by: Daniel J Blueman Signed-off-by: Eric Anholt Tested-by: Chris Wilson [v1] Tested-by: Eric Anholt [v1,v3] (incidence of the bug with a testcase went from avg 2/1000 to 0/12651 in the latest test run (plus more for v1)) Tested-by: Kenneth Graunke [v1] Tested-by: Robert Hooker [v1] Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=33394 Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/i915_irq.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -1567,6 +1567,16 @@ static void ironlake_irq_preinstall(stru drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private; I915_WRITE(HWSTAM, 0xeffe); + if (IS_GEN6(dev)) { + /* Workaround stalls observed on Sandy Bridge GPUs by + * making the blitter command streamer generate a + * write to the Hardware Status Page for + * MI_USER_INTERRUPT. This appears to serialize the + * previous seqno write out before the interrupt + * happens. + */ + I915_WRITE(GEN6_BLITTER_HWSTAM, ~GEN6_BLITTER_USER_INTERRUPT); + } /* XXX hotplug from PCH */