Le ven., mars 4 2022 at 18:51:14 +0100, H. Nikolaus Schaller
<hns@xxxxxxxxxxxxx> a écrit :
Hi Paul, Neil,
Am 04.03.2022 um 17:47 schrieb Paul Cercueil <paul@xxxxxxxxxxxxxxx>:
From what I understood in Nikolaus' last message, HDMI hotplug is
actually correctly detected, so there's no need for polling. What is
missing is the call to drm_kms_helper_hotplug_event *somewhere*, so
that the information is correctly relayed to userspace.
Exactly.
As Maxime pointed out it should already be called by
drm_helper_hpd_irq_event() in dw_hdmi_irq() but isn't
because mode_config.poll_enabled isn't enabled.
So we can either
a) enable mode_config.poll_enabled so that it is called by
drm_helper_hpd_irq_event() or
b) make drm_kms_helper_hotplug_event() being called explicitly in
dw_hdmi_irq().
We could guard that by mode_config.poll_enabled to avoid
drm_kms_helper_hotplug_event()
being called twice (but I think the "changed" mechanism will take
care of).
I think this issue can be fixed by calling
drm_bridge_connector_enable_hpd() on the connector in
ingenic-drm-drv.c.
I don't see yet how this would solve it, but it may work.
dw_hdmi_irq() calls drm_bridge_hpd_notify(), which would call
bridge->hpd_cb() if it was non-NULL.
Calling drm_bridge_connector_enable_hpd() will set the bridge->hpd_cb()
callback to point to drm_bridge_connector_hpd_cb(), which itself will
call drm_kms_helper_hotplug_event(). Therefore, all that is missing is
one call to drm_bridge_connector_enable_hpd().
Cheers,
-Paul
Anyways, this all is a missing feature (sometimes called "bug") of
the *dw-hdmi driver* and IMHO
neither of the connector nor the ingenic-drm-drv.
So I think it should not be solved outside dw-hdmi.
BR and thanks,
Nikolaus
