[Intel-gfx] [PATCH 5/7] drm/i915: disable CLKOUT_DP when it's not needed

[Paulo Zanoni]

2013/7/12 Daniel Vetter <daniel at ffwll.ch>:
> On Fri, Jul 12, 2013 at 02:19:40PM -0300, Paulo Zanoni wrote:
>> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
>>
>> We currently don't support HDMI clock bending nor use SSC for DP or
>> HDMI on Haswell, so the only case where we need CLKOUT_DP is for VGA.
>>
>> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
>
> Just an aside: One of the many plans on my todo is to move the refclk
> updates into the global_modeset_resources callback and only enable the
> refclocks we actually need for the given configuration. Entirely different
> patch series though.

Yeah, that's a good idea. And for that, we'll need this series merged :)

> -Daniel
>
>> ---
>>  drivers/gpu/drm/i915/intel_display.c | 38 ++++++++++++++++++++++++++++++++----
>>  1 file changed, 34 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>> index 5f3b636..059c9a8 100644
>> --- a/drivers/gpu/drm/i915/intel_display.c
>> +++ b/drivers/gpu/drm/i915/intel_display.c
>> @@ -5305,6 +5305,36 @@ static void lpt_enable_clkout_dp(struct drm_device *dev, bool with_spread,
>>       mutex_unlock(&dev_priv->dpio_lock);
>>  }
>>
>> +/* Sequence to disable CLKOUT_DP */
>> +static void lpt_disable_clkout_dp(struct drm_device *dev)
>> +{
>> +     struct drm_i915_private *dev_priv = dev->dev_private;
>> +     uint32_t tmp;
>> +
>> +     mutex_lock(&dev_priv->dpio_lock);
>> +
>> +     if (IS_ULT(dev_priv->dev)) {
>> +             tmp = intel_sbi_read(dev_priv, SBI_GEN0, SBI_ICLK);
>> +             tmp &= ~SBI_GEN0_ENABLE;
>> +             intel_sbi_write(dev_priv, SBI_GEN0, tmp, SBI_ICLK);
>> +     } else {
>> +             tmp = intel_sbi_read(dev_priv, SBI_DBUFF0, SBI_ICLK);
>> +             tmp &= ~SBI_DBUFF0_ENABLE;
>> +             intel_sbi_write(dev_priv, SBI_DBUFF0, tmp, SBI_ICLK);
>> +     }
>> +
>> +     tmp = intel_sbi_read(dev_priv, SBI_SSCCTL, SBI_ICLK);
>> +     if (!(tmp & SBI_SSCCTL_PATHALT)) {
>> +             tmp |= SBI_SSCCTL_PATHALT;
>> +             intel_sbi_write(dev_priv, SBI_SSCCTL, tmp, SBI_ICLK);
>> +             udelay(32);
>> +     }
>> +     tmp |= SBI_SSCCTL_DISABLE;
>> +     intel_sbi_write(dev_priv, SBI_SSCCTL, tmp, SBI_ICLK);
>> +
>> +     mutex_unlock(&dev_priv->dpio_lock);
>> +}
>> +
>>  static void lpt_init_pch_refclk(struct drm_device *dev)
>>  {
>>       struct drm_mode_config *mode_config = &dev->mode_config;
>> @@ -5319,10 +5349,10 @@ static void lpt_init_pch_refclk(struct drm_device *dev)
>>               }
>>       }
>>
>> -     if (!has_vga)
>> -             return;
>> -
>> -     lpt_enable_clkout_dp(dev, true, true);
>> +     if (has_vga)
>> +             lpt_enable_clkout_dp(dev, true, true);
>> +     else
>> +             lpt_disable_clkout_dp(dev);
>>  }
>>
>>  /*
>> --
>> 1.8.1.2
>>
>> _______________________________________________
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>> Intel-gfx at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch



-- 
Paulo Zanoni