Re: [PATCH v5 21/22] drm/vc4: vec: Add support for more analog TV standards

Mateusz Kwiatkowski
2022-10-16T19:03:49Z

Hi Maxime,

W dniu 13.10.2022 o 15:19, Maxime Ripard pisze:
> From: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
>
> Add support for the following composite output modes (all of them are
> somewhat more obscure than the previously defined ones):
>
> - NTSC_443 - NTSC-style signal with the chroma subcarrier shifted to
>   4.43361875 MHz (the PAL subcarrier frequency). Never used for
>   broadcasting, but sometimes used as a hack to play NTSC content in PAL
>   regions (e.g. on VCRs).
> - PAL_N - PAL with alternative chroma subcarrier frequency,
>   3.58205625 MHz. Used as a broadcast standard in Argentina, Paraguay
>   and Uruguay to fit 576i50 with colour in 6 MHz channel raster.
> - PAL60 - 480i60 signal with PAL-style color at normal European PAL
>   frequency. Another non-standard, non-broadcast mode, used in similar
>   contexts as NTSC_443. Some displays support one but not the other.

The current version actually does not support PAL-60. Proper PAL-60 output from
VEC requires configuring it differently than for regular PAL. We have unified
the PAL and PAL-60 modes for the "TV mode" property, but the code here has not
been adjusted appropriately.

I'll try to submit an additional patch that fixes this shortly.

> - SECAM - French frequency-modulated analog color standard; also have
>   been broadcast in Eastern Europe and various parts of Africa and Asia.
>   Uses the same 576i50 timings as PAL.
>
> Also added some comments explaining color subcarrier frequency
> registers.
>
> Acked-by: Noralf Trønnes <noralf@tronnes.org>
> Signed-off-by: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> ---
(snip)

Best regards,
Mateusz Kwiatkowski