[PATCH] drm/i915: Set the required VFMUNIT clock gating disable on Ironlake.

[PATCH] drm/i915: Set the required VFMUNIT clock gating disable on Ironlake.

[Eric Anholt]

It's required by the specs, but we don't know why.  Let's not find out
why.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
 drivers/gpu/drm/i915/i915_reg.h      |    3 +++
 drivers/gpu/drm/i915/intel_display.c |    2 ++
 2 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 9e077fe..e8b00a3 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2512,6 +2512,9 @@
 # define MARIUNIT_CLOCK_GATE_DISABLE		(1 << 18)
 # define SVSMUNIT_CLOCK_GATE_DISABLE		(1 << 1)
 
+#define PCH_3DCGDIS1		0x46024
+# define VFMUNIT_CLOCK_GATE_DISABLE		(1 << 11)
+
 #define FDI_PLL_FREQ_CTL        0x46030
 #define  FDI_PLL_FREQ_CHANGE_REQUEST    (1<<24)
 #define  FDI_PLL_FREQ_LOCK_LIMIT_MASK   0xfff00
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 3cdc9f0..3923738 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5768,6 +5768,8 @@ void intel_init_clock_gating(struct drm_device *dev)
 			I915_WRITE(PCH_3DCGDIS0,
 				   MARIUNIT_CLOCK_GATE_DISABLE |
 				   SVSMUNIT_CLOCK_GATE_DISABLE);
+			I915_WRITE(PCH_3DCGDIS1,
+				   VFMUNIT_CLOCK_GATE_DISABLE);
 		}
 
 		I915_WRITE(PCH_DSPCLK_GATE_D, dspclk_gate);
-- 
1.7.2.3

Re: [PATCH] drm/i915: Set the required VFMUNIT clock gating disable on Ironlake.

[Chris Wilson]

On Tue, 14 Dec 2010 10:06:46 -0800, Eric Anholt <eric@anholt.net> wrote:
> It's required by the specs, but we don't know why.  Let's not find out
> why.

Any feel at all for the level of impact of not disabling power gating of
the VFM unit? Random hang? Incorrect output? I'm not even sure what the
VFM unit is.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre

Re: [PATCH] drm/i915: Set the required VFMUNIT clock gating disable on Ironlake.

[Eric Anholt]

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On Tue, 14 Dec 2010 18:19:30 +0000, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> On Tue, 14 Dec 2010 10:06:46 -0800, Eric Anholt <eric@anholt.net> wrote:
> > It's required by the specs, but we don't know why.  Let's not find out
> > why.
> 
> Any feel at all for the level of impact of not disabling power gating of
> the VFM unit? Random hang? Incorrect output? I'm not even sure what the
> VFM unit is.
> -Chris

No clue.

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