On Thu, 20 Oct 2022 at 10:14, <maxime@xxxxxxxxxx> wrote:
>
> From: Dom Cobley <popcornmix@xxxxxxxxx>
>
> At least the 4096x2160@60Hz mode requires some overclocking that isn't
> available by default, even if hdmi_enable_4kp60 is enabled.
>
> Let's add some logic to detect whether we can satisfy the core clock
> requirements for that mode, and prevent it from being used otherwise.
>
> Signed-off-by: Dom Cobley <popcornmix@xxxxxxxxx>
> Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
Reviewed-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/vc4/vc4_drv.h | 6 ++++++
> drivers/gpu/drm/vc4/vc4_hdmi.c | 11 +++++++++--
> drivers/gpu/drm/vc4/vc4_hvs.c | 3 +++
> 3 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
> index 8b2b1af565f9..72a6b7151d23 100644
> --- a/drivers/gpu/drm/vc4/vc4_drv.h
> +++ b/drivers/gpu/drm/vc4/vc4_drv.h
> @@ -347,6 +347,12 @@ struct vc4_hvs {
> * available.
> */
> bool vc5_hdmi_enable_scrambling;
> +
> + /*
> + * 4096x2160@60 requires a core overclock to work, so register
> + * whether that is sufficient.
> + */
> + bool vc5_hdmi_enable_4096by2160;
> };
>
> struct vc4_plane {
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index afe3daa2173e..fd3730ea976f 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -1753,6 +1753,7 @@ vc4_hdmi_sink_supports_format_bpc(const struct vc4_hdmi *vc4_hdmi,
>
> static enum drm_mode_status
> vc4_hdmi_encoder_clock_valid(const struct vc4_hdmi *vc4_hdmi,
> + const struct drm_display_mode *mode,
> unsigned long long clock)
> {
> const struct drm_connector *connector = &vc4_hdmi->connector;
> @@ -1765,6 +1766,12 @@ vc4_hdmi_encoder_clock_valid(const struct vc4_hdmi *vc4_hdmi,
> if (!vc4->hvs->vc5_hdmi_enable_scrambling && clock > HDMI_14_MAX_TMDS_CLK)
> return MODE_CLOCK_HIGH;
>
> + /* 4096x2160@60 is not reliable without overclocking core */
> + if (!vc4->hvs->vc5_hdmi_enable_4096by2160 &&
> + mode->hdisplay > 3840 && mode->vdisplay >= 2160 &&
> + drm_mode_vrefresh(mode) >= 50)
> + return MODE_CLOCK_HIGH;
> +
> if (info->max_tmds_clock && clock > (info->max_tmds_clock * 1000))
> return MODE_CLOCK_HIGH;
>
> @@ -1799,7 +1806,7 @@ vc4_hdmi_encoder_compute_clock(const struct vc4_hdmi *vc4_hdmi,
> unsigned long long clock;
>
> clock = vc4_hdmi_encoder_compute_mode_clock(mode, bpc, fmt);
> - if (vc4_hdmi_encoder_clock_valid(vc4_hdmi, clock) != MODE_OK)
> + if (vc4_hdmi_encoder_clock_valid(vc4_hdmi, mode, clock) != MODE_OK)
> return -EINVAL;
>
> vc4_state->tmds_char_rate = clock;
> @@ -1962,7 +1969,7 @@ vc4_hdmi_encoder_mode_valid(struct drm_encoder *encoder,
> (mode->hsync_end % 2) || (mode->htotal % 2)))
> return MODE_H_ILLEGAL;
>
> - return vc4_hdmi_encoder_clock_valid(vc4_hdmi, mode->clock * 1000);
> + return vc4_hdmi_encoder_clock_valid(vc4_hdmi, mode, mode->clock * 1000);
> }
>
> static const struct drm_encoder_helper_funcs vc4_hdmi_encoder_helper_funcs = {
> diff --git a/drivers/gpu/drm/vc4/vc4_hvs.c b/drivers/gpu/drm/vc4/vc4_hvs.c
> index 300ac0b57571..a68913f76687 100644
> --- a/drivers/gpu/drm/vc4/vc4_hvs.c
> +++ b/drivers/gpu/drm/vc4/vc4_hvs.c
> @@ -818,6 +818,9 @@ static int vc4_hvs_bind(struct device *dev, struct device *master, void *data)
> if (max_rate >= 550000000)
> hvs->vc5_hdmi_enable_scrambling = true;
>
> + if (max_rate >= 600000000)
> + hvs->vc5_hdmi_enable_4096by2160 = true;
> +
> hvs->max_core_rate = max_rate;
>
> ret = clk_prepare_enable(hvs->core_clk);
>
> --
> b4 0.10.1
