releases/3.1.5/drm-i915-turn-on-another-required-clock-gating-bit-on-gen6.patch

   1 From 9ca1d10d748e56964de95e3ed80211b192f56cf4 Mon Sep 17 00:00:00 2001
   2 From: Eric Anholt <eric@anholt.net>
   3 Date: Mon, 7 Nov 2011 16:07:05 -0800
   4 Subject: drm/i915: Turn on another required clock gating bit on gen6.
   5
   6 From: Eric Anholt <eric@anholt.net>
   7
   8 commit 9ca1d10d748e56964de95e3ed80211b192f56cf4 upstream.
   9
  10 Unlike the previous one, I don't have known testcases it fixes.  I'd
  11 rather not go through the same debug cycle on whatever testcases those
  12 might be.
  13
  14 Signed-off-by: Eric Anholt <eric@anholt.net>
  15 Signed-off-by: Keith Packard <keithp@keithp.com>
  16 Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
  17
  18 ---
  19  drivers/gpu/drm/i915/i915_reg.h      |    1 +
  20  drivers/gpu/drm/i915/intel_display.c |    7 ++++++-
  21  2 files changed, 7 insertions(+), 1 deletion(-)
  22
  23 --- a/drivers/gpu/drm/i915/i915_reg.h
  24 +++ b/drivers/gpu/drm/i915/i915_reg.h
  25 @@ -3403,6 +3403,7 @@
  26
  27  #define GEN6_UCGCTL2                           0x9404
  28  # define GEN6_RCPBUNIT_CLOCK_GATE_DISABLE              (1 << 12)
  29 +# define GEN6_RCCUNIT_CLOCK_GATE_DISABLE               (1 << 11)
  30
  31  #define GEN6_RPNSWREQ                          0xA008
  32  #define   GEN6_TURBO_DISABLE                   (1<<31)
  33 --- a/drivers/gpu/drm/i915/intel_display.c
  34 +++ b/drivers/gpu/drm/i915/intel_display.c
  35 @@ -7888,8 +7888,13 @@ static void gen6_init_clock_gating(struc
  36          * some amount of runtime in the Mesa "fire" demo, and Unigine
  37          * Sanctuary and Tropics, and apparently anything else with
  38          * alpha test or pixel discard.
  39 +        *
  40 +        * According to the spec, bit 11 (RCCUNIT) must also be set,
  41 +        * but we didn't debug actual testcases to find it out.
  42          */
  43 -       I915_WRITE(GEN6_UCGCTL2, GEN6_RCPBUNIT_CLOCK_GATE_DISABLE);
  44 +       I915_WRITE(GEN6_UCGCTL2,
  45 +                  GEN6_RCPBUNIT_CLOCK_GATE_DISABLE |
  46 +                  GEN6_RCCUNIT_CLOCK_GATE_DISABLE);
  47
  48         /*
  49          * According to the spec the following bits should be