[Intel-gfx] Thinkpad T420 and single/dual channel lvds
Adam Jackson
ajax at redhat.com
Fri Mar 16 20:55:52 CET 2012
On 3/15/12 10:42 AM, Takashi Iwai wrote:
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index f851db7..314af26 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -356,6 +356,23 @@ static const intel_limit_t intel_limits_ironlake_display_port = {
> .find_pll = intel_find_pll_ironlake_dp,
> };
>
> +static bool is_dual_link_lvds(struct drm_i915_private *dev_priv,
> + unsigned int reg)
> +{
> + /* 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;
Would slightly prefer if this was more like:
if (dev_priv->bios_lvds_val)
return !!(dev_priv->bios_lvds_val & LVDS_CLKB_POWER_MASK);
Since that way it eliminates some useless register reads in the normal
case even for single-link. Not going to insist on it though.
Looks really good otherwise, thanks!
Reviewed-by: Adam Jackson <ajax at redhat.com>
- ajax
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