Re: [PATCH 05/10] ARM: tegra: Enable eDP for Venice2

[Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>]

On 12/20/2013 03:20 AM, Thierry Reding wrote:
> On Thu, Dec 19, 2013 at 02:40:23PM -0700, Stephen Warren wrote:
>> On 12/19/2013 09:06 AM, Thierry Reding wrote:
>>> Venice2 has a 12.9" (2560x1700) panel connected to the eDP output of the
>>> Tegra124. The panel has an EDID to describe the video timings but needs
>>> a few extra nodes to get the backlight to come up.
>>
>> I started with next-20131219, merged your latest drm/for-next branch,
>> and this doesn't seem to work.
>>
>> With Laxman's regulator patch applied and your 1/10 dropped since it's a
>> duplicate, the LCD backlight doesn't light up. I extracted the following
>> from this patch to fix Laxman's regulator definitions:
>>
>>                         gpio = <&gpio TEGRA_GPIO(P, 2) GPIO_ACTIVE_LOW>;
>> +                       enable-active-high;
>>                 };
>>
>> and the backlight does light up, but that's all.
>>
>> With Laxman's regulator patch reverted and your patch 1/10 applied to
>> replace it, I see the backlight working without having to manually fix
>> up the device tree. However, that's still all; nothing is actually
>> displayed.
> 
> Nothing's displayed because the driver isn't actually there yet. It's
> still stuck in internal review for some reason.
> 
> I should've probably been explicit about that.
> 
>> Again, can you please rebase this whole series on the latest Tegra
>> for-3.14/dt and sort out the issues? Thanks.
> 
> Grmpf... yes, I suppose I'll go do that then. That's exactly the reason
> why I said the other day that we shouldn't be adding regulators
> willy-nilly without any means of actually testing.
> 
> We've seen this happen on Dalmore before, and it's now happening with
> Venice2. The same applies to pinmux. If we keep having to correct the
> DTS files because it was all applied at once "to avoid churn" we're not
> actually gaining anything.

Sorry. My original thoughts were that the schematics and specifications
are all completely available (internally) for these boards, as is a
complete known-working/tested DT for the board, so it's a relatively
simple exercise to take that and upstream it. As such, if we just did
all that in one go, it'd reduce churn by making a single patch to do the
whole thing once, rather than having lots of patches that build the
configuration up bit-by-bit. There's also the issue that we really do
need to set up the complete pinctrl configuration once up-front, to
avoid conflicts due to the same HW block being routed to multiple sets
of pins.

That's what I was thinking anyway. Evidently, I was wrong:-( Sorry.