[PATCH v12 2/9] drm/ingenic: Add support for JZ4780 and HDMI output

[Paul Cercueil]

Le mer., févr. 2 2022 at 13:33:15 +0100, H. Nikolaus Schaller 
<hns at goldelico.com> a écrit :
> 
> 
>>  Am 02.02.2022 um 13:28 schrieb Paul Cercueil <paul at crapouillou.net>:
>> 
>> 
>> 
>>  Le mer., févr. 2 2022 at 13:17:14 +0100, H. Nikolaus Schaller 
>> <hns at goldelico.com> a écrit :
>>>  Hi Paul,
>>>>  Am 02.02.2022 um 13:06 schrieb Paul Cercueil 
>>>> <paul at crapouillou.net>:
>>>>  Hi Nikolaus,
>>>>>>>  @@ -446,6 +454,9 @@ static int 
>>>>>>> ingenic_drm_plane_atomic_check(struct drm_plane *plane,
>>>>>>>  	if (!crtc)
>>>>>>>  		return 0;
>>>>>>>  +	if (plane == &priv->f0)
>>>>>>>  +		return -EINVAL;
>>>>>>  This will break JZ4725B -> JZ4770 SoCs, the f0 plane is 
>>>>>> perfectly usable there.
>>>>>  Hm. I think it was your request/proposal to add this [1]?
>>>>  Because otherwise with your current patchset the f0 plane does 
>>>> not work *on JZ4780*.
>>>  Not that I am eager to fix that, but...
>>>  maybe it could be better to fix than having the check and -EINVAL 
>>> depend on SoC compatible string
>>>  (or some new flag in soc_info. plane_f0_not_working)?
>> 
>>  Totally agree! A proper fix would be much better. A 
>> "plane_f0_not_working" in the meantime is OK with me.
> 
> Ok, then I'll prepare a v13 with plane_f0_not_working.
> 
>> 
>>  Note that there are other things not working with your current 
>> implementation, for instance you cannot set the X/Y start position 
>> of the f1 plane, which means it's only really usable for fullscreen 
>> desktop/windows.
> 
> Is setting x/y possible for the other SoC?

Yes. They support different x/y positions, sizes, and pixel format for 
both f0, f1 and IPU planes.

-Paul

>> 
>>>>  It does work on older SoCs.
>>>>>  What I have forgotten is why the f0 plane should not be usable 
>>>>> for jz4780.
>>>>  We return an error here to prevent userspace from using the f0 
>>>> plane until it's effectively working on the JZ4780.
>>>  Well, what would be not working with that plane if user-space 
>>> would try to use it?
>> 
>>  From what I remember, it wouldn't show anything on screen, and 
>> after that trying to use the f1 plane wouldn't work either.
> 
> Ok. That may become a big project to fix. So let's do step 1 first.
> 
> BR and thanks,
> NIkolaus
>