Re: [PATCH 3/3] drm/i915/bxt: Use the bypass frequency if there are no active pipes.

Ville Syrjälä
2015-10-27T13:31:27Z

On Tue, Oct 27, 2015 at 02:26:33PM +0100, Maarten Lankhorst wrote:
> Now that pixel clock is set to 0 when there are no active pipes it's
> easy to set the bypass frequency for this case.
>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> ---
> drivers/gpu/drm/i915/intel_display.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index e9a94ddcba73..ddac097cd08a 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -5925,7 +5925,6 @@ static int broxton_calc_cdclk(struct drm_i915_private *dev_priv,
> /*
> * FIXME:
> * - remove the guardband, it's not needed on BXT
> - * - set 19.2MHz bypass frequency if there are no active pipes
> */
> if (max_pixclk > 576000*9/10)
> return 624000;
> @@ -5935,8 +5934,10 @@ static int broxton_calc_cdclk(struct drm_i915_private *dev_priv,
> return 384000;
> else if (max_pixclk > 144000*9/10)
> return 288000;
> - else
> + else if (max_pixclk)
> return 144000;
> + else
> + return 19200;

I think we want to test this on actual hardware before putting it in.
Also we might want to do something similar on other platforms too.

> }
>
> /* Compute the max pixel clock for new configuration. Uses atomic state if
> --
> 2.1.0

--
Ville Syrjälä
Intel OTC