[Intel-gfx] Thinkpad T420 and single/dual channel lvds
Chris Wilson
chris at chris-wilson.co.uk
Thu Mar 15 14:25:08 CET 2012
On Thu, 15 Mar 2012 14:15:54 +0100, Takashi Iwai <tiwai at suse.de> wrote:
> +static bool is_dual_link_lvds(struct drm_i915_private *dev_priv)
> +{
> + /* BIOS should set the proper LVDS register value at boot, but
> + * in reality, it doesn't set the value when the lid is closed;
> + * thus when a machine is booted with the lid closed, the LVDS
> + * reg value can't be trusted. So we need to check "the value
> + * to be set" in VBT at first.
> + */
> + if ((dev_priv->bios_lvds_val & LVDS_CLKB_POWER_MASK) ==
> + LVDS_CLKB_POWER_UP)
> + return true;
> + if ((I915_READ(PCH_LVDS) & LVDS_CLKB_POWER_MASK) ==
This is either PCH_LVDS or LVDS depending on the generation.
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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