[PATCH v7 0/8] drm: sun8i: Add DE2 HDMI video support

[Jernej Skrabec]

Hi Laurent,

Dne torek, 29. november 2016 23.56.31 UTC+1 je oseba Laurent Pinchart 
napisala:
>
> Hi Jernej, 
>
> (CC'ing Kieran Bingham) 
>
> On Tuesday 29 Nov 2016 14:47:20 Jernej Skrabec wrote: 
> > Dne torek, 29. november 2016 22.37.03 UTC+1 je oseba Maxime Ripard 
> napisala: 
> > > On Tue, Nov 29, 2016 at 11:18:35AM +0100, Jean-Francois Moine wrote: 
> > >> This patchset series adds HDMI video support to the Allwinner 
> > >> sun8i SoCs which include the display engine 2 (DE2). 
> > >> The driver contains the code for the A83T and H3 SoCs, and 
> > >> some H3 boards, but it could be used/extended for other SoCs 
> > >> (A64, H2, H5) and boards (Banana PIs, Orange PIs). 
> > > 
> > > Honestly, I'm getting a bit worried by the fact that you ignore 
> > > reviews. 
> > > 
> > > On the important reviews that you got that are to be seen as major 
> > > 
> > > issues that block the inclusion, we have: 
> > >   - The fact that the HDMI driver is actually just a designware IP, 
> > >     and while you should use the driver that already exists, you just 
> > >     duplicated all that code. 
> > 
> > That might be hard thing to do. A83T fits perfectly, but H3 and newer 
> SoCs 
> > do not. They are using completely different HDMI phy. Decoupling 
> controller 
> > and phy code means rewritting a good portion of the code, unless some 
> tricks 
> > are applied, like calling phy function pointers, if they are defined. 
>
> Same HDMI TX but different HDMI TX PHY ? Kieran is working on decoupling 
> the 
> PHY configuration code for a Renesas SoC, that might be of interest to 
> you. 
>

Exactly. I'm developing only U-Boot driver, but Jean-Francois will probably
have more interest in this.
 

>
> > Register addresses also differ, but that can be easily solved by using 
> > undocumented magic value to restore them. 
>
> I love that :-) 
>
>
Is it allowed to use magic number which was found in binary blob? I'm new in
all this.
 

> > >   - The fact that you ignored Rob (v6) and I (v5) comment on using OF 
> > >     graph to model the connection between the display engine and the 
> > >     TCON. Something that Laurent also pointed out in this version. 
> > >   
> > >   - The fact that you ignored that you needed an HDMI connector node 
> > >     as a child of the HDMI controller. This has been reported by Rob 
> > >     (v6) and yet again in this version by Laurent. 
> > >   
> > >   - And finally the fact that we can't have several display engine in 
> > >     parallel, if needs be. This has happened in the past already on 
> > >     Allwinner SoCs, so it's definitely something we should consider in 
> > >     the DT bindings, since we can't break them. 
> > > 
> > > Until those are fixed, I cannot see how this driver can be merged, 
> > > unfortunately. 
>
> -- 
> Regards, 
>
> Laurent Pinchart 
>
>
Best regards,
Jernej Škrabec 
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