[PATCH v4 1/4] drm/rockchip: vop: limit maximium resolution to hardware capabilities

[Sascha Hauer]

On Tue, Feb 07, 2023 at 10:16:57AM +0100, Dan Johansen wrote:
> 
> Den 07.02.2023 kl. 09.44 skrev Sascha Hauer:
> > The different VOP variants support different maximum resolutions. Reject
> > resolutions that are not supported by a specific variant.
> > 
> > This hasn't been a problem in the upstream driver so far as 1920x1080
> > has been the maximum resolution supported by the HDMI driver and that
> > resolution is supported by all VOP variants. Now with higher resolutions
> > supported in the HDMI driver we have to limit the resolutions to the
> > ones supported by the VOP.
> > 
> > The actual maximum resolutions are taken from the Rockchip downstream
> > Kernel.
> 
> So just so I understand it, this will allow only up to 1080p on rk3399 or
> will it change something that allows higher resolutions, but with lower
> clock/pixel rates?

This patch is not about bandwidth limitations, only limitations in the
maximum resolution.

The RK3399 has two VOPs, VOPB and VOPL. The latter can only do 1080p
whereas the former can do up to 4k at 30. This patch limits the allowed
resolutions to what the VOP can do. So when your application chooses
VOPB you should see 4k at 30 as long as your monitor supports it.

In my testing weston has chosen VOPB and thus shows 4k at 30, but I can't
tell if it does so because weston is smart enough, or just happens to
default to the VOPB.

Sascha

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