Re: [PATCH] drm/sun4i: Workaround TCON TOP conflict between DE0 and DE1

[John Watts <contact@jookia.org>]

On Fri, Nov 08, 2024 at 07:36:16PM +0530, Parthiban wrote:
> To add, 0x20 will be DE0 <--> LCD0 and DE1 <--> TV0. Below note (copied from
> R40) states the priority of the DE selection, which fails to work? Not sure,
> may be disabling CORE1_SCLK_GATE and CORE1_HCLK_GATE in de2-clk helps.
> 
> With A133 following the same as T113 with single mixer without TV, still
> sets 0x20 in vendor kernel.
> 
> copied from R40:
> Note: The priority of DE0 is higher than DE1.
> If TCON_LCD0 selects DE0 and DE1 as source at the same time, then
> DE0 will be used for the source of TCON_LCD0.

Hi there,

Yes that was a pretty bad typo, I meant to say DE1 to TV0
The prioritization seems broken in the T113 at least, it's racy from
what I see in testing. I should note this in the patch too.

I looked at the datasheets and kernel code briefly: I can't seem to
figure out what SCLK/HCLK gating does and I don't think the kernel
touches these registers which are gated by default.

> Thanks,
> Parthiban

John Watts