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