drm/vc4: hdmi: Don't try disabling SCDC on Pi0-3.

Commit Message

Maxime Ripard Jan. 27, 2022, 1:45 p.m. UTC

From: Dave Stevenson <[e-mail]>

The code that set the scdc_enabled flag to ensure it was
disabled at boot time also ran on Pi0-3 where there is no
SCDC support. This lead to a warning in vc4_hdmi_encoder_post_crtc_disable
due to vc4_hdmi_disable_scrambling being called and trying to
read (and write) register HDMI_SCRAMBLER_CTL which doesn't
exist on those platforms.

Only set the flag should the interface be configured to support
more than HDMI 1.4.

Fixes: 1998646129fa ("drm/vc4: hdmi: Introduce a scdc_enabled flag")
Signed-off-by: Dave Stevenson <[e-mail]>
Signed-off-by: Maxime Ripard <[e-mail]>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Maxime Ripard Feb. 3, 2022, 3:06 p.m. UTC | #1

On Thu, 27 Jan 2022 14:45:59 +0100, Maxime Ripard wrote:
> From: Dave Stevenson <[e-mail]>
> 
> The code that set the scdc_enabled flag to ensure it was
> disabled at boot time also ran on Pi0-3 where there is no
> SCDC support. This lead to a warning in vc4_hdmi_encoder_post_crtc_disable
> due to vc4_hdmi_disable_scrambling being called and trying to
> read (and write) register HDMI_SCRAMBLER_CTL which doesn't
> exist on those platforms.
> 
> [...]

Applied to drm/drm-misc (drm-misc-fixes).

Thanks!
Maxime

Patch

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 33ecfa1e3661..0ee446df50a0 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -2534,7 +2534,8 @@  static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
 	 * vc4_hdmi_disable_scrambling() will thus run at boot, make
 	 * sure it's disabled, and avoid any inconsistency.
 	 */
-	vc4_hdmi->scdc_enabled = true;
+	if (variant->max_pixel_clock > HDMI_14_MAX_TMDS_CLK)
+		vc4_hdmi->scdc_enabled = true;
 
 	ret = variant->init_resources(vc4_hdmi);
 	if (ret)