[Nouveau] [PATCH (repost) 2/5] drm_dp_cec: add note about good MegaChips 2900 CEC support

[Lyude Paul]

Reviewed-by: Lyude Paul <lyude at redhat.com>

On Fri, 2018-08-17 at 16:11 +0200, Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil at cisco.com>
> 
> A big problem with DP CEC-Tunneling-over-AUX is that it is tricky
> to find adapters with a chipset that supports this AND where the
> manufacturer actually connected the HDMI CEC line to the chipset.
> 
> Add a mention of the MegaChips 2900 chipset which seems to support
> this feature well.
> 
> Signed-off-by: Hans Verkuil <hans.verkuil at cisco.com>
> ---
>  drivers/gpu/drm/drm_dp_cec.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_dp_cec.c b/drivers/gpu/drm/drm_dp_cec.c
> index 1407b13a8d5d..8a718f85079a 100644
> --- a/drivers/gpu/drm/drm_dp_cec.c
> +++ b/drivers/gpu/drm/drm_dp_cec.c
> @@ -16,7 +16,9 @@
>   * here. Quite a few active (mini-)DP-to-HDMI or USB-C-to-HDMI adapters
>   * have a converter chip that supports CEC-Tunneling-over-AUX (usually the
>   * Parade PS176), but they do not wire up the CEC pin, thus making CEC
> - * useless.
> + * useless. Note that MegaChips 2900-based adapters appear to have good
> + * support for CEC tunneling. Those adapters that I have tested using
> + * this chipset all have the CEC line connected.
>   *
>   * Sadly there is no way for this driver to know this. What happens is
>   * that a /dev/cecX device is created that is isolated and unable to see