[Nouveau] [PATCH 5/6] kms/nv50: detect HDMI max MHz correctly

[Ilia Mirkin]

This removes user control to force a hdmimhz. Given the vast variety
of hardware and display configurations out there, I don't see how a
patch like this won't blow up in our faces.

I'm not saying we shouldn't do it -- we should attempt to respect the
various maximums in the vbios, but until we get a solid handle on
things, we should allow more user-configurability, not less, for the
case where we get it wrong.

2018-07-20 11:17 GMT-04:00 Karol Herbst <kherbst at redhat.com>:
> Signed-off-by: Karol Herbst <kherbst at redhat.com>
> ---
>  drm/nouveau/dispnv50/disp.c     | 5 +++++
>  drm/nouveau/nouveau_connector.c | 5 +++++
>  drm/nouveau/nouveau_encoder.h   | 4 ++++
>  3 files changed, 14 insertions(+)
>
> diff --git a/drm/nouveau/dispnv50/disp.c b/drm/nouveau/dispnv50/disp.c
> index 6f41a6a0..3a960664 100644
> --- a/drm/nouveau/dispnv50/disp.c
> +++ b/drm/nouveau/dispnv50/disp.c
> @@ -1433,7 +1433,12 @@ nv50_sor_create(struct drm_connector *connector, struct dcb_output *dcbe,
>         case DCB_OUTPUT_LVDS: type = DRM_MODE_ENCODER_LVDS; break;
>         case DCB_OUTPUT_DP:
>                 nv_encoder->dp.no_interlace = caps->dp[or].no_interlace;
> +               type = DRM_MODE_ENCODER_TMDS;
> +               break;
>         case DCB_OUTPUT_TMDS:
> +               nv_encoder->tmds.max_mhz = caps->tmds[or].max_mhz;
> +               type = DRM_MODE_ENCODER_TMDS;
> +               break;
>         default:
>                 type = DRM_MODE_ENCODER_TMDS;
>                 break;
> diff --git a/drm/nouveau/nouveau_connector.c b/drm/nouveau/nouveau_connector.c
> index 074e6d52..a955f225 100644
> --- a/drm/nouveau/nouveau_connector.c
> +++ b/drm/nouveau/nouveau_connector.c
> @@ -980,9 +980,14 @@ static unsigned
>  get_tmds_link_bandwidth(struct drm_connector *connector, bool hdmi)
>  {
>         struct nouveau_connector *nv_connector = nouveau_connector(connector);
> +       struct nouveau_encoder *nv_encoder = nv_connector->detected_encoder;
>         struct nouveau_drm *drm = nouveau_drm(connector->dev);
>         struct dcb_output *dcb = nv_connector->detected_encoder->dcb;
>
> +       /* cap to 297MHz until we figure out HDMI 2.0 */
> +       if (nv_encoder->tmds.max_mhz)
> +               return nv_encoder->tmds.max_mhz * 1000;
> +
>         if (hdmi) {
>                 if (nouveau_hdmimhz > 0)
>                         return nouveau_hdmimhz * 1000;
> diff --git a/drm/nouveau/nouveau_encoder.h b/drm/nouveau/nouveau_encoder.h
> index f74af5ce..fbef9dc0 100644
> --- a/drm/nouveau/nouveau_encoder.h
> +++ b/drm/nouveau/nouveau_encoder.h
> @@ -65,6 +65,10 @@ struct nouveau_encoder {
>                         int link_bw;
>                         bool no_interlace;
>                 } dp;
> +
> +               struct {
> +                       uint16_t max_mhz;
> +               } tmds;
>         };
>
>         void (*enc_save)(struct drm_encoder *encoder);
> --
> 2.17.1
>
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