drm/bridge: Synopsys DW-HDMI bridge driver for the Ingenic JZ4780 (was Re: Specialising the Synopsys DW-HDMI bridge driver for the Ingenic JZ4780)

[Paul Cercueil]

Le lun. 24 août 2020 à 14:38, Ezequiel Garcia 
<ezequiel at vanguardiasur.com.ar> a écrit :
> On Mon, 24 Aug 2020 at 13:05, H. Nikolaus Schaller 
> <hns at goldelico.com> wrote:
>> 
>>  Hi Ezequiel,
>> 
>>  > Am 24.08.2020 um 15:46 schrieb Ezequiel Garcia 
>> <ezequiel at vanguardiasur.com.ar>:
>>  >
>>  > On Fri, 21 Aug 2020 at 19:24, Paul Cercueil 
>> <paul at crapouillou.net> wrote:
>>  >>
>>  >>
>>  >>
>>  >> Le sam. 22 août 2020 à 0:11, Paul Boddie <paul at boddie.org.uk> a
>>  >> écrit :
>>  >>
>>  >> If you send clean patches, there's no reason for me not to merge 
>> them.
>>  >>
>>  >
>>  > I'd really like to see HDMI support on my CI20 being merged. 
>> Thank to
>>  > recent ingenic-drm work and thanks for Paul Boddie and Nikolaus 
>> work,
>>  > the patches are IMO quite clean.
>> 
>>  I have done some testing and it appears that it only works if DRM is
>>  compiled into the kernel. At least in my setup. If DRM and/or HDMI 
>> are made
>>  modules there is no video or code doesn't compile completely.
>> 
>>  We have to analyse that further.
>> 
> 
> Ah! That's true.
> 
> The fix is just re-organizing the code a bit. Just pushed a possible
> fix for that (following the IPU handling by Paul Cercueil),
> please feel free to test this:
> 
> https://gitlab.collabora.com/linux/0day/-/commits/jz4780-drm-hdmi-module-fix-v5.9-rc2
> 
> FWIW, my test setup uses mainline vanilla U-Boot v2020.07.
> The kernel is loaded via TFTP. Debian mipsel is mounted via NFS
> (which means dm9000 works). I'm testing with weston and modetest.
> 
> Note that enabling DRM_INGENIC_IPU will make the driver
> fail to load, as the IPU is not optional (and not present on 
> ci20.dts).
> A minor thing to fix.

Actually that's a bug, the IPU should be optional. I'll come up with a 
fix.

>>  And it seems to differ significantly from what Paul has developed 
>> recently
>>  to make it work. It seems to be quite lucky that we have a working 
>> setup now :)
>> 
>>  > Nikolaus, Paul: Do you have plans to submit these?
>> 
>>  Yes, as soon as we are sure that it works (and when it doesn't).
>> 
>>  But thanks to your work it is now much easier to improve things, 
>> since we
>>  are no longer looking for a break-through but just have to avoid 
>> regressions.
>> 
>>  > If not, I'll be happy to get them out the door for review.
>> 
>>  Let it mature a little first and have it tested on more setups and 
>> rebased
>>  to mainline v5.9-rc2 :)
>> 

DRM drivers follow their own schedule, you should rebase to 
drm-misc-next instead.

Cheers,
-Paul