Change in ...coreboot[master]: lenovo/x230: introduce FHD variant

[Sergey Alirzaev (Code Review)]

Sergey Alirzaev has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/28950 )

Change subject: lenovo/x230: introduce FHD variant
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Patch Set 7:
> Patch Set 7:
> > At the moment the fhd mod board requires 3.3V from a separate cable, which causes elevated power consumption especially when the lid is closed or the machine is sleeping.
> > This is because the tapped source is always on.
> > Though if it was possible to provide power through the VCC3P power rail instead, the board could be supplied with power only when the display is supposed to be on. This would eliminate the extra cable and only requires that J1 jumper is closed on the board. I tried it myself and also measured a the corresponding pad but there seems to be no voltage present from the lvds connector with the current state of this patch.
> >
> > Maybe someone more knowledgeable has an idea on how to implement this?
>
> Did you also measure the voltage when Linux has booted?
> I would assume that it works in Linux. If that is the
> case, all that is left (as mentioned before) is to make
> libgfxinit aware of the panel at the DP connector (needs
> some restructuring, though).

I have some hopefully relevant code:
--- a/src/northbridge/intel/sandybridge/gma.c
+++ b/src/northbridge/intel/sandybridge/gma.c
@@ -557,6 +557,10 @@ static void gma_pm_init_post_vbios(struct device *dev)
                gtt_write(0xc4030, reg32);
        }

+       /* Turn the panel power on using eDP VDD Override */
+       gtt_write(PCH_PP_CONTROL, gtt_read(PCH_PP_CONTROL) | PCH_PP_UNLOCK | EDP_FORCE_VDD);
+       udelay(125000); /* And wait until it powers up */
+
        /* Setup Panel Power On Delays */
        reg32 = gtt_read(0xc7208);
        if (!reg32) {