From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20111207161215.528198772@clark.kroah.org> Date: Wed, 07 Dec 2011 08:11:11 -0800 From: Greg KH To: , Cc: , , , Eric Anholt , Keith Packard Subject: [009/104] drm/i915: Turn on a required 3D clock gating bit on Sandybridge. In-Reply-To: <20111207161246.GA10995@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Anholt commit 406478dc911e16677fbd9c84d1d50cdffbc031ab upstream. Fixes rendering failures in Unigine Tropics and Sanctuary and the mesa "fire" demo. Signed-off-by: Eric Anholt Signed-off-by: Keith Packard Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/i915_reg.h | 3 +++ drivers/gpu/drm/i915/intel_display.c | 9 +++++++++ 2 files changed, 12 insertions(+) --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -3401,6 +3401,9 @@ #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) --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -7882,6 +7882,15 @@ static void gen6_init_clock_gating(struc 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: