diff mbox series

[4/8] drm/vc4: hdmi: Check and warn if we can't reach 4kp60 frequencies

Message ID 20210225155909.1853812-5-maxime@cerno.tech (mailing list archive)
State New, archived
Headers show
Series drm/vc4: hdmi: Support the 4k @ 60Hz modes | expand

Commit Message

Maxime Ripard Feb. 25, 2021, 3:59 p.m. UTC
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>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 17 +++++++++++++++++
 drivers/gpu/drm/vc4/vc4_hdmi.h |  8 ++++++++
 2 files changed, 25 insertions(+)

Comments

Dave Stevenson Feb. 25, 2021, 4:38 p.m. UTC | #1
Hi Maxime

On Thu, 25 Feb 2021 at 15:59, 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).

force_turbo isn't the right way to go about this as it permanently
bumps all the clocks up, even if running the display at VGA.

> 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>
> ---
>  drivers/gpu/drm/vc4/vc4_hdmi.c | 17 +++++++++++++++++
>  drivers/gpu/drm/vc4/vc4_hdmi.h |  8 ++++++++
>  2 files changed, 25 insertions(+)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index b5bc742993a4..f05f6da286f7 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -953,6 +953,9 @@ 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;
> @@ -972,6 +975,9 @@ 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;
>  }
>
> @@ -1986,6 +1992,17 @@ 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_get_max_rate(vc4->hvs->core_clk);
> +
> +               if (max_rate < 550000000) {
> +                       drm_warn(drm, "The core clock cannot reach frequencies high enough to support 4k @ 60Hz.");
> +                       drm_warn(drm, "Please change your config.txt file to add hdmi_enable_4kp60 and force_turbo");

Do we really want to warn in bind? Again you could have a VGA
resolution monitor attached but that would trigger this warning.
Can we warn (once) on processing the mode list and filtering out a clk
> HDMI_14_MAX_TMDS_CLK mode instead?

And mentioning force_turbo is again wrong.

  Dave

> +                       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;
> --
> 2.29.2
>
Maxime Ripard March 2, 2021, 1:01 p.m. UTC | #2
Hi Dave,

Thanks for your review

On Thu, Feb 25, 2021 at 04:38:37PM +0000, Dave Stevenson wrote:
> On Thu, 25 Feb 2021 at 15:59, 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).
> 
> force_turbo isn't the right way to go about this as it permanently
> bumps all the clocks up, even if running the display at VGA.

so enable_hdmi_4kp60 is enough? 

> > 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>
> > ---
> >  drivers/gpu/drm/vc4/vc4_hdmi.c | 17 +++++++++++++++++
> >  drivers/gpu/drm/vc4/vc4_hdmi.h |  8 ++++++++
> >  2 files changed, 25 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> > index b5bc742993a4..f05f6da286f7 100644
> > --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> > +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> > @@ -953,6 +953,9 @@ 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;
> > @@ -972,6 +975,9 @@ 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;
> >  }
> >
> > @@ -1986,6 +1992,17 @@ 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_get_max_rate(vc4->hvs->core_clk);
> > +
> > +               if (max_rate < 550000000) {
> > +                       drm_warn(drm, "The core clock cannot reach frequencies high enough to support 4k @ 60Hz.");
> > +                       drm_warn(drm, "Please change your config.txt file to add hdmi_enable_4kp60 and force_turbo");
> 
> Do we really want to warn in bind? Again you could have a VGA
> resolution monitor attached but that would trigger this warning.
> Can we warn (once) on processing the mode list and filtering out a clk
> > HDMI_14_MAX_TMDS_CLK mode instead?

That's a good idea indeed, I'll rework the patch to do that

Thanks!
Maxime
Dave Stevenson March 2, 2021, 3:10 p.m. UTC | #3
On Tue, 2 Mar 2021 at 13:02, Maxime Ripard <maxime@cerno.tech> wrote:
>
> Hi Dave,
>
> Thanks for your review
>
> On Thu, Feb 25, 2021 at 04:38:37PM +0000, Dave Stevenson wrote:
> > On Thu, 25 Feb 2021 at 15:59, 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).
> >
> > force_turbo isn't the right way to go about this as it permanently
> > bumps all the clocks up, even if running the display at VGA.
>
> so enable_hdmi_4kp60 is enough?

No, but force_turbo=1 is the wrong way to go about fixing that.

I'll start a thread with Dom & Tim to discuss the best way of doing
this. Immediate thoughts are that either vc4_hdmi needs to request the
core clock be increased, or potentially the firmware could note the
boosted BVB rate and increase core accordingly.

  Dave

> > > 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>
> > > ---
> > >  drivers/gpu/drm/vc4/vc4_hdmi.c | 17 +++++++++++++++++
> > >  drivers/gpu/drm/vc4/vc4_hdmi.h |  8 ++++++++
> > >  2 files changed, 25 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> > > index b5bc742993a4..f05f6da286f7 100644
> > > --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> > > +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> > > @@ -953,6 +953,9 @@ 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;
> > > @@ -972,6 +975,9 @@ 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;
> > >  }
> > >
> > > @@ -1986,6 +1992,17 @@ 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_get_max_rate(vc4->hvs->core_clk);
> > > +
> > > +               if (max_rate < 550000000) {
> > > +                       drm_warn(drm, "The core clock cannot reach frequencies high enough to support 4k @ 60Hz.");
> > > +                       drm_warn(drm, "Please change your config.txt file to add hdmi_enable_4kp60 and force_turbo");
> >
> > Do we really want to warn in bind? Again you could have a VGA
> > resolution monitor attached but that would trigger this warning.
> > Can we warn (once) on processing the mode list and filtering out a clk
> > > HDMI_14_MAX_TMDS_CLK mode instead?
>
> That's a good idea indeed, I'll rework the patch to do that
>
> Thanks!
> Maxime
diff mbox series

Patch

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index b5bc742993a4..f05f6da286f7 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -953,6 +953,9 @@  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;
@@ -972,6 +975,9 @@  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;
 }
 
@@ -1986,6 +1992,17 @@  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_get_max_rate(vc4->hvs->core_clk);
+
+		if (max_rate < 550000000) {
+			drm_warn(drm, "The core clock cannot reach frequencies high enough to support 4k @ 60Hz.");
+			drm_warn(drm, "Please change your config.txt file to add hdmi_enable_4kp60 and force_turbo");
+			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;