On Tue, Dec 17, 2013 at 10:52:24PM +0200, Imre Deak wrote:
> VGA detection requires the reference clock to be on, so make sure this
> is the case.
> 
> This fixes VGA hotplug/manual detection where all pipes are off and so
> we would normally disable all clocks.
> 
> v2:
> - Instead of disabling PSR clock gating, force the reference clock on
>   through the DPLL_A register. (Kin Chan S <kin.s.c...@intel.com>)
> 
> Reported-by: Joonas Lahtinen <joonas.lahti...@linux.intel.com>
> Signed-off-by: Imre Deak <imre.d...@intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 14 ++++++++++++--
>  drivers/gpu/drm/i915/intel_pm.c      |  5 +++++
>  2 files changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c 
> b/drivers/gpu/drm/i915/intel_display.c
> index 674fd43..f3a0a7e 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -1507,9 +1507,15 @@ static void vlv_disable_pll(struct drm_i915_private 
> *dev_priv, enum pipe pipe)
>       /* Make sure the pipe isn't still relying on us */
>       assert_pipe_disabled(dev_priv, pipe);
>  
> -     /* Leave integrated clock source enabled */
> +     /*
> +      * Leave integrated clock source enabled for pipe B and the reference
> +      * clock for pipe A. The latter is needed for VGA hotplug / manual
> +      * detection.
> +      */
>       if (pipe == PIPE_B)
>               val = DPLL_INTEGRATED_CRI_CLK_VLV;
> +     else
> +             val = DPLL_REFA_CLK_ENABLE_VLV;
>       I915_WRITE(DPLL(pipe), val);
>       POSTING_READ(DPLL(pipe));
>  }
> @@ -4984,7 +4990,11 @@ static void vlv_update_pll(struct intel_crtc *crtc)
>  
>       vlv_dpio_write(dev_priv, pipe, VLV_PLL_DW11(pipe), 0x87871000);
>  
> -     /* Enable DPIO clock input */
> +     /*
> +      * Enable DPIO clock input. We should never disable the reference
> +      * clock for pipe A, since VGA hotplug / manual detection depends
> +      * on it. Set it here for state tracking.
> +      */
>       dpll = DPLL_EXT_BUFFER_ENABLE_VLV | DPLL_REFA_CLK_ENABLE_VLV |
>               DPLL_VGA_MODE_DIS | DPLL_INTEGRATED_CLOCK_VLV;
>       /* We should never disable this, set it here for state tracking */
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index fccd7a8..1c1de83 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4933,6 +4933,11 @@ static void valleyview_init_clock_gating(struct 
> drm_device *dev)
>  
>       I915_WRITE(DSPCLK_GATE_D, VRHUNIT_CLOCK_GATE_DISABLE);
>  
> +     /* Force the reference clock on for VGA hotplug / manual detection */
> +     val = I915_READ(DPLL(PIPE_A));
> +     val |= DPLL_REFA_CLK_ENABLE_VLV;
> +     I915_WRITE(DPLL(PIPE_A), val);
> +

Maybe put this part into intel_init_dpio()?

I can't really comment on the rest since I have no idea why it works.

>       /* WaDisableEarlyCull:vlv */
>       I915_WRITE(_3D_CHICKEN3,
>                  _MASKED_BIT_ENABLE(_3D_CHICKEN_SF_DISABLE_OBJEND_CULL));
> -- 
> 1.8.4
> 
> _______________________________________________
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> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC
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