The parameter starfive_crtc_enable_vblan is empty on VisionFive. However, the
parameter is required when setting DRM in the Open Harmony operating system. I hope
StarFive can add this parameter.
Figure 1. starfive_crtc_enable_vblan is empty
SoC
JH7100
SBC
VisionFive
Software
USDK V2.0.0
Cause
Customer misunderstanding.
Theoretically, we do not necessarily need to have the
WaitVBlank logic.
WaitVBlank is not an appropriate solution, due to the
following uncertainties.
You cannot specify the CRTC with WaitVBlank.
You cannot make sure how many vblanks you have to wait.
Solution
Instead of the WaitVBlank method, StarFive is using the
wait page flip complete method by
select to know the page flip
complete. Our DRM framework supports the current page flip logic.
Procedure
Use the following command to verify that DRM framework supports the page flip logic:
