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[PATCH 1/2] drm/vc4: Reject HDMI modes with too high of clocks.

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  [PATCH 1/2] drm/vc4: Reject HDMI modes with too high of clocks. Eric Anholt <eric@anholt.net> - 2017-09-21 01:00 +0200
    [PATCH 2/2] drm/vc4: Update kerneldoc about CEC and power management Eric Anholt <eric@anholt.net> - 2017-09-21 01:00 +0200

#1736220 — [PATCH 1/2] drm/vc4: Reject HDMI modes with too high of clocks.

Peter Robinson reported issues on Fedora with 4k monitors not having
their modes filtered down to 1920x1080 on Raspberry Pi.  Hopefully
this resolves that.

Cc: Peter Robinson <pbrobinson@redhat.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
---

Note: This is an untested patch, since I'm away from hardware
currently.

 drivers/gpu/drm/vc4/vc4_hdmi.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index fa37a1c07cf6..65826a4f208e 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -694,7 +694,22 @@ static void vc4_hdmi_encoder_enable(struct drm_encoder *encoder)
 	}
 }
 
+static enum drm_mode_status
+vc5_hdmi_encoder_mode_valid(struct drm_encoder *crtc,
+			    const struct drm_display_mode *mode)
+{
+	/* HSM clock must be 108% of the pixel clock.  Additionally,
+	 * the AXI clock needs to be at least 25% of pixel clock, but
+	 * HSM ends up being the limiting factor.
+	 */
+	if (mode->clock > HSM_CLOCK_FREQ / (1000 * 108 / 100))
+		return MODE_CLOCK_HIGH;
+
+	return MODE_OK;
+}
+
 static const struct drm_encoder_helper_funcs vc4_hdmi_encoder_helper_funcs = {
+	.mode_valid = vc5_hdmi_encoder_mode_valid,
 	.disable = vc4_hdmi_encoder_disable,
 	.enable = vc4_hdmi_encoder_enable,
 };
-- 
2.14.1

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#1736221 — [PATCH 2/2] drm/vc4: Update kerneldoc about CEC and power management

Boris had added full power management, and then Hans partially removed
it to enable CEC, so update the docs about both.

Cc: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Eric Anholt <eric@anholt.net>
---
 drivers/gpu/drm/vc4/vc4_hdmi.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 65826a4f208e..ce18384c6be3 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -33,13 +33,9 @@
  * interconnect) bus to the encoder side for insertion into the video
  * blank regions.
  *
- * The driver's HDMI encoder does not yet support power management.
- * The HDMI encoder's power domain and the HSM/pixel clocks are kept
- * continuously running, and only the HDMI logic and packet ram are
- * powered off/on at disable/enable time.
- *
- * The driver does not yet support CEC control, though the HDMI
- * encoder block has CEC support.
+ * Note that HDMI CEC requires that the HSM clock be running even when
+ * not scanning out, so that input can be processed.  The PHY is still
+ * powered down when not scanning out, though.
  */
 
 #include <drm/drm_atomic_helper.h>
-- 
2.14.1

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