[Intel-gfx] [PATCH 15/49] drm/i915/bxt: add GEN8_HDCUNIT_CLOCK_GATE_DISABLE_HDCREQ workaround

[Nick Hoath]

On 17/03/2015 09:39, Imre Deak wrote:
> From: Ben Widawsky <benjamin.widawsky at intel.com>
>
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_reg.h | 1 +
>   drivers/gpu/drm/i915/intel_pm.c | 4 +++-
>   2 files changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 3369a11..b7ba061 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6104,6 +6104,7 @@ enum skl_disp_power_wells {
>   #define GEN8_UCGCTL6				0x9430
>   #define   GEN8_GAPSUNIT_CLOCK_GATE_DISABLE	(1<<24)
>   #define   GEN8_SDEUNIT_CLOCK_GATE_DISABLE	(1<<14)
> +#define   GEN8_HDCUNIT_CLOCK_GATE_DISABLE_HDCREQ (1<<28)
>
>   #define GEN6_GFXPAUSE				0xA000
>   #define GEN6_RPNSWREQ				0xA008
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index d5dd0b3..52d3c02 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -103,10 +103,12 @@ static void bxt_init_clock_gating(struct drm_device *dev)
>   	/*
>   	 * FIXME:
>   	 * GEN8_SDEUNIT_CLOCK_GATE_DISABLE applies on A0 only.
> +	 * GEN8_HDCUNIT_CLOCK_GATE_DISABLE_HDCREQ applies on 3x6 GT SKUs only.
>   	 */
>   	 /* WaDisableSDEUnitClockGating:bxt */

I can't find where WaDisableSDEUnitClockGating is listed as required for 
BXT?

>   	I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) |
> -		   GEN8_SDEUNIT_CLOCK_GATE_DISABLE);
> +		   GEN8_SDEUNIT_CLOCK_GATE_DISABLE |
> +		   GEN8_HDCUNIT_CLOCK_GATE_DISABLE_HDCREQ);
>
>   }
>
>