Re: [PATCH 05/15] drm/vc4: hdmi: Restore cec physical address on reconnect

On Fri, 18 Dec 2020 at 14:21, Dave Stevenson dave.stevenson@raspberrypi.com wrote:

Hi Maxime & Dom

On Thu, 10 Dec 2020 at 13:47, Maxime Ripard maxime@cerno.tech wrote:

...

From: Dom Cobley popcornmix@gmail.com

Currently we call cec_phys_addr_invalidate on a hotplug deassert. That may be due to a TV power cycling, or an AVR being switched on (and switching edid).

This makes CEC unusable since our controller wouldn't have a physical address anymore.

Set it back up again on the hotplug assert.

Fixes: 15b4511a4af6 ("drm/vc4: add HDMI CEC support") Signed-off-by: Dom Cobley popcornmix@gmail.com Signed-off-by: Maxime Ripard maxime@cerno.tech

---

drivers/gpu/drm/vc4/vc4_hdmi.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index 28b78ea885ea..eff3bac562c6 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -136,20 +136,29 @@ static enum drm_connector_status vc4_hdmi_connector_detect(struct drm_connector *connector, bool force) { struct vc4_hdmi *vc4_hdmi = connector_to_vc4_hdmi(connector);

•   bool connected = false;
  
    if (vc4_hdmi->hpd_gpio) {
            if (gpio_get_value_cansleep(vc4_hdmi->hpd_gpio) ^
                vc4_hdmi->hpd_active_low)
  

•                   return connector_status_connected;
  

•           cec_phys_addr_invalidate(vc4_hdmi->cec_adap);
  

•           return connector_status_disconnected;
  

•   }
  

•   if (drm_probe_ddc(vc4_hdmi->ddc))
  

•           return connector_status_connected;
  

•                   connected = true;
  

•   } else if (drm_probe_ddc(vc4_hdmi->ddc))
  

•           connected = true;
    if (HDMI_READ(HDMI_HOTPLUG) & VC4_HDMI_HOTPLUG_CONNECTED)
  

This needs to become an "else if(...". It used to be that all the other paths would return, so were mutually exclusive to this. Now they set a thing and keep going we need to avoid reading the register should there be a HPD gpio or the ddc probe succeeds. Memory says that otherwise Pi3 always reports connected.

I fixed this in a downstream patch already - https://github.com/raspberrypi/linux/commit/d345caec1e9b2317b9cd7eb5b92ae453...

Otherwise fine.

Dave

...

•           connected = true;
  

•   if (connected) {
  

•           if (connector->status != connector_status_connected) {
  

•                   struct edid *edid = drm_get_edid(connector, vc4_hdmi->ddc);
  

•                   if (edid) {
  

•                           cec_s_phys_addr_from_edid(vc4_hdmi->cec_adap, edid);
  

•                           vc4_hdmi->encoder.hdmi_monitor = drm_detect_hdmi_monitor(edid);
  

•                           drm_connector_update_edid_property(connector, edid);
  

Actually looking at this again in the context of the other changes, do we need to call drm_connector_update_edid_property() here?

We've just called drm_get_edid() to get the edid, and that calls drm_connector_update_edid_property() as well [1] Updating vc4_hdmi->encoder.hdmi_monitor may be necessary. It's otherwise done in vc4_hdmi_connector_get_modes, which I sort of expect to be called almost immediately by the framework when connector_detect returns "connected". I haven't checked if that is guaranteed though.

vc4_hdmi_connector_get_modes also includes a manual call to drm_connector_update_edid_property after having just called drm_get_edid, so that one feels redundant too.

Dave

[1] https://elixir.bootlin.com/linux/v5.10/source/drivers/gpu/drm/drm_edid.c#L20...

...

•                           kfree(edid);
  

•                   }
  

•           }
            return connector_status_connected;
  

•   }
    cec_phys_addr_invalidate(vc4_hdmi->cec_adap);
    return connector_status_disconnected;
  

}

2.28.0