[PATCH v3 0/3] drm/rockchip: dw_hdmi: Add 4k at 30 support

[Sascha Hauer]

On Wed, Feb 01, 2023 at 09:23:56AM +0900, FUKAUMI Naoki wrote:
> hi,
> 
> I'm trying this patch series with 6.1.x kernel. it works fine on rk356x
> based boards (ROCK 3), but it has a problem on rk3399 boards (ROCK 4).
> 
> on rk3399 with this patch, I can see large noise area (about one third right
> side of the screen) at 4k at 30. 1080p works fine as same as before.
> 
> can someone reproduce this problem on rk3399?

Ok, I could easily reproduce the problem here.

The RK3399 has two VOPs, vopb(ig) and vopl(ittle). Only the former can
do 4k at 30 while the latter can only do 1080p. Unfortunately vopl is used
by default. We can force using vopb by disabling vopl in the device tree
and get a good 4k at 30 picture then. The other possibility I found is to
use the other CRTC with modetest. I have no idea how we could set the
default to vopb.

I guess a first step would be to limit the maximum resolution of vopl
to what the hardware can do. We would likely end up with 1080p by
default then for the applications.

Sascha

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