Re: [PATCH] clocksource: Ingenic: Add high resolution timer support for SMP.

[Paul Boddie <paul@boddie.org.uk>]

On Tuesday 19. May 2020 22.11.10 Paul Cercueil wrote:
> 
> I took the liberty to clean your patch so that it doesn't create a
> struct ingenic_tcu per CPU timer.
> 
> Tested, and fully working on the JZ4770 with CONFIG_SMP disabled, and
> also with CONFIG_SMP enabled (even though JZ4770 has only one CPU) with
> a fixed smp.c and USB disabled (otherwise it crashes at boot).

Thanks for looking at this and also your continuing work with the DRM driver. 
I'll try and look a bit more at the DRM driver for the JZ4780 and see what I 
am doing wrong with regard to JZ4780-specific configuration. In principle, 
there should not be any, but I don't really have the full picture (literally 
and also in terms of documentation or understanding).

One thing that seems to be done with the Imagination/Ingenic drivers is dual 
DMA channel initialisation. Usually, this seems to be necessary only for dual-
panel configurations, and I wonder whether there is some kind of requirement 
for the same arrangement when using the HDMI output.

Another thing that is done involves setting a foreground, which might be 
relevant to your more recent contributions adding IPU support. Again, I don't 
really understand why this seems necessary, but the documentation hardly 
provides any details that might explain it.

Paul