[Intel-gfx] [PATCH 4/4] drm/i915: Allow HDMI+HDMI cloning on g4x

[Rodrigo Vivi]

On Mon, Mar 3, 2014 at 11:15 AM,  <ville.syrjala at linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> BSpec is a bit unclear whether HDMI+HDMI cloning should work on g4x.
> Tests on real hardware say that it does. Since g4x can't send
> infoframes to more than one HDMI port anyway, we don't lose anything
> by allow it.

I hope this isn't a case that will work for some and blow up in others.
Anyway i'm in favor of this patch! +1

>
> For PCH platforms BSpec explicitly forbids HDMI+HDMI cloning.

To be honest I couldn't find this info, but sounds resonable and patch
is on the safe side for platforms with PCH.

So, feel free to use
Reviewed-by: Rodrigo Vivi <rodrigo.vivi at gmail.com>

>
> Whether HDMI+HDMI cloning might also work on VLV is a bit unclear, but
> since we'd at least lose the capability of sending infoframes to more
> than one cloned HDMI port, it doesn't seem like a good idea to allow it.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=73850
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_hdmi.c | 7 +++++++
>  1 file changed, 7 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> index 9dacb33..4eb30d8 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -1316,6 +1316,13 @@ void intel_hdmi_init(struct drm_device *dev, int hdmi_reg, enum port port)
>         intel_encoder->type = INTEL_OUTPUT_HDMI;
>         intel_encoder->crtc_mask = (1 << 0) | (1 << 1) | (1 << 2);
>         intel_encoder->cloneable = 1 << INTEL_OUTPUT_ANALOG;
> +       /*
> +        * BSpec is unclear about HDMI+HDMI cloning on g4x, but it seems
> +        * to work on real hardware. And since g4x can send infoframes to
> +        * only one port anyway, nothing is lost by allowing it.
> +        */
> +       if (IS_G4X(dev))
> +               intel_encoder->cloneable |= 1 << INTEL_OUTPUT_HDMI;
>
>         intel_dig_port->port = port;
>         intel_dig_port->hdmi.hdmi_reg = hdmi_reg;
> --
> 1.8.3.2
>
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-- 
Rodrigo Vivi
Blog: http://blog.vivi.eng.br