kmssink: fix kmssink fail to start when not connect display

Submitted by Haihua Hu @JaredHu

Link to original bug (#791374)

Description

Currently kmssink will fail when not connect display to device. Get display connected status from drm connector, drop all buffer when display not connected to make pipeline can run.

Version: 1.12.x

Haihua Hu @JaredHu submitted a patch:

Get display connected status from drm connector, drop all buffer when display not connected

Patch 365228, "kmssink: fix kmssink fail to start when not connect display":
0001-kmssink-fix-kmssink-fail-to-start-when-not-connect-d.patch

Nicolas Dufresne @ndufresne reviewed patch 365228:

Am I right to think that if the display get connected later, nothing happens ?

Víctor Manuel Jáquez Leal @vjaquez said:

(In reply to Nicolas Dufresne (stormer) from comment 2)

Review of attachment 365228 [details] [review]:

Am I right to think that if the display get connected later, nothing happens
?

It seems so. Because self->display_connected is only TRUE at _start(), which is called when the sink changes from NULL to READY state.

So, what's the purpose of this patch? keep the pipeline working even if nothing is displayed? why?

Haihua Hu @JaredHu said:

(In reply to Nicolas Dufresne (stormer) from comment 2)

Review of attachment 365228 [details] [review]:

Am I right to think that if the display get connected later, nothing happens
?

Temporary, nothing happened, if so, we need add reset() to get display parameters when display connection status changed. This patch can only make pipeline working for audio chain.

Nicolas Dufresne @ndufresne said:

Ok, I'd say this patch is incomplete then. In this form it's not useful. Your app could use fakesink and have some code that detect the display connection.

Dear friends, are there any updates to fix thís issues of kmssink ? I am using gstreamer 1.14 and my kmssink cannot start without a display. Thank you very muchs !

Any updates would result in notification on this issue or an associated MR. The lack of either means there are no updates on this issue.

added Bad Plugins labels