From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751956Ab1KHAHL (ORCPT ); Mon, 7 Nov 2011 19:07:11 -0500 Received: from gabe.freedesktop.org ([131.252.210.177]:39871 "EHLO gabe.freedesktop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750863Ab1KHAHI (ORCPT ); Mon, 7 Nov 2011 19:07:08 -0500 From: Eric Anholt To: linux-kernel@vger.kernel.org Cc: keithp@keithp.com, Eric Anholt , stable@kernel.org Subject: [PATCH 1/2] drm/i915: Turn on a required 3D clock gating bit on Sandybridge. Date: Mon, 7 Nov 2011 16:07:04 -0800 Message-Id: <1320710825-3408-1-git-send-email-eric@anholt.net> X-Mailer: git-send-email 1.7.7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Fixes rendering failures in Unigine Tropics and Sanctuary and the mesa "fire" demo. Signed-off-by: Eric Anholt Cc: stable@kernel.org --- drivers/gpu/drm/i915/i915_reg.h | 3 +++ drivers/gpu/drm/i915/intel_display.c | 9 +++++++++ 2 files changed, 12 insertions(+), 0 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 8adb560..6ba7ea6 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -3397,6 +3397,9 @@ #define GT_FIFO_FREE_ENTRIES 0x120008 #define GT_FIFO_NUM_RESERVED_ENTRIES 20 +#define GEN6_UCGCTL2 0x9404 +# define GEN6_RCPBUNIT_CLOCK_GATE_DISABLE (1 << 12) + #define GEN6_RPNSWREQ 0xA008 #define GEN6_TURBO_DISABLE (1<<31) #define GEN6_FREQUENCY(x) ((x)<<25) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 04411ad..fde7c42 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -7850,6 +7850,15 @@ static void gen6_init_clock_gating(struct drm_device *dev) I915_WRITE(WM2_LP_ILK, 0); I915_WRITE(WM1_LP_ILK, 0); + /* According to the BSpec vol1g, bit 12 (RCPBUNIT) clock + * gating disable must be set. Failure to set it results in + * flickering pixels due to Z write ordering failures after + * some amount of runtime in the Mesa "fire" demo, and Unigine + * Sanctuary and Tropics, and apparently anything else with + * alpha test or pixel discard. + */ + I915_WRITE(GEN6_UCGCTL2, GEN6_RCPBUNIT_CLOCK_GATE_DISABLE); + /* * According to the spec the following bits should be * set in order to enable memory self-refresh and fbc: -- 1.7.7