Re: [PATCH v2 3/5] drm/vc4: hdmi: Check and warn if we can't reach 4kp60 frequencies

Hi Maxime

On Thu, 18 Mar 2021 at 09:29, Maxime Ripard maxime@cerno.tech wrote:

In order to reach the frequencies needed to output at 594MHz, the firmware needs to be configured with the appropriate parameters in the config.txt file (enable_hdmi_4kp60 and force_turbo).

Let's detect it at bind time, warn the user if we can't, and filter out the relevant modes.

Signed-off-by: Maxime Ripard maxime@cerno.tech

Reviewed-by: Dave Stevenson dave.stevenson@raspberrypi.com

---

drivers/gpu/drm/vc4/vc4_hdmi.c | 26 ++++++++++++++++++++++++++ drivers/gpu/drm/vc4/vc4_hdmi.h | 8 ++++++++ 2 files changed, 34 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index eaee853bb404..0924a1b9e186 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -210,6 +210,18 @@ static int vc4_hdmi_connector_get_modes(struct drm_connector *connector) ret = drm_add_edid_modes(connector, edid); kfree(edid);

•   if (vc4_hdmi->disable_4kp60) {
  

•           struct drm_device *drm = connector->dev;
  

•           struct drm_display_mode *mode;
  

•           list_for_each_entry(mode, &connector->probed_modes, head) {
  

•                   if ((mode->clock * 1000) > HDMI_14_MAX_TMDS_CLK) {
  

•                           drm_warn_once(drm, "The core clock cannot reach frequencies high enough to support 4k @ 60Hz.");
  

•                           drm_warn_once(drm, "Please change your config.txt file to add hdmi_enable_4kp60.");
  

•                   }
  

•           }
  

•   }
  

•   return ret;
  

}

@@ -959,6 +971,9 @@ static int vc4_hdmi_encoder_atomic_check(struct drm_encoder *encoder, if (pixel_rate > vc4_hdmi->variant->max_pixel_clock) return -EINVAL;

•   if (vc4_hdmi->disable_4kp60 && (pixel_rate > HDMI_14_MAX_TMDS_CLK))
  

•           return -EINVAL;
  

•   vc4_state->pixel_rate = pixel_rate;
  
    return 0;
  

@@ -978,6 +993,9 @@ vc4_hdmi_encoder_mode_valid(struct drm_encoder *encoder, if ((mode->clock * 1000) > vc4_hdmi->variant->max_pixel_clock) return MODE_CLOCK_HIGH;

•   if (vc4_hdmi->disable_4kp60 && ((mode->clock * 1000) > HDMI_14_MAX_TMDS_CLK))
  

•           return MODE_CLOCK_HIGH;
  

•   return MODE_OK;
  

}

@@ -1992,6 +2010,14 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data) vc4_hdmi->disable_wifi_frequencies = of_property_read_bool(dev->of_node, "wifi-2.4ghz-coexistence");

•   if (variant->max_pixel_clock == 600000000) {
  

•           struct vc4_dev *vc4 = to_vc4_dev(drm);
  

•           long max_rate = clk_round_rate(vc4->hvs->core_clk, 550000000);
  

•           if (max_rate < 550000000)
  

•                   vc4_hdmi->disable_4kp60 = true;
  

•   }
  

•   if (vc4_hdmi->variant->reset)
            vc4_hdmi->variant->reset(vc4_hdmi);
  
  

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h index 3cebd1fd00fc..3cd021136402 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.h +++ b/drivers/gpu/drm/vc4/vc4_hdmi.h @@ -154,6 +154,14 @@ struct vc4_hdmi { */ bool disable_wifi_frequencies;

•   /*
  

•    * Even if HDMI0 on the RPi4 can output modes requiring a pixel
  

•    * rate higher than 297MHz, it needs some adjustments in the
  

•    * config.txt file to be able to do so and thus won't always be
  

•    * available.
  

•    */
  

•   bool disable_4kp60;
  

•   struct cec_adapter *cec_adap;
    struct cec_msg cec_rx_msg;
    bool cec_tx_ok;
  

-- 2.30.2