DRA76P: Display Multiplexing

Mandar Pande

Part Number: DRA76P

Hello,

I am using DRA76x SoC for my project and in my design I have interfaced one HDMI display with the HDMI port of the Display Subsystem on the SoC.

On this display, I need to project four screens. Something like this:

Related image

How can I acheive this using only one HDMI display port?

Thanks,

Mandar

over 8 years ago

0 Yordan Kamenov over 8 years ago

TI__Mastermind 42515 points

Hi Mandar,

which SDK you use?

Regards,
Yordan

0 Brijesh Jadav over 8 years ago in reply to Yordan Kamenov

TI__Guru**** 496655 points

You could use four display pipelines and display different contents at different positions.

Rgds,

Brijesh

0 Mandar Pande over 8 years ago in reply to Yordan Kamenov

Prodigy 60 points

Automotive Linux SDK v3.04

0 Mandar Pande over 8 years ago in reply to Brijesh Jadav

Prodigy 60 points

Hi Brijesh,

How exactly can we do that?

Thanks,
Mandar

0 Brijesh Jadav over 8 years ago in reply to Mandar Pande

TI__Guru**** 496655 points

Hi Mandar,

i am not sure on Linux, but essentially there are four display pipelines, 3 video and one grpx, you could connect these pipelines to the overlay manager, which outputs to the HDMI VENC. Then you need to configure each of the pipeline to output 1/4 display frame size and position them on the final display.

Rgds,
Brijesh

0 Subhajit Paul over 8 years ago in reply to Brijesh Jadav

TI__Expert 7015 points

Mandar,

I am assuming you are well familiar with DRM modesetting APIs. You can boot your kernel after adding omapdrm.num_crtc=1, use dra76-evm.dtb, and you can use the following pseudo code to achive the following

create a DRM dumb buffer of size (WxH). Render in the rectangle (0,0 to W/2,H/2). Create a DRM FB using this buffer. Lets call it FBP

create 3 DRM dumb buffers of size (W/2,H/2). Render in rectangles (0,0 to W/2,H/2) in each of them. Create DRM FBs from each of these buffers. Lets call them FB1, FB2, FB3

Call drmModePageFlip with FBP

Call drmModeSetPlane on each of the three overlay planes with one FB each. position them properly.

Regards,

Subhajit

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DRA76P: Display Multiplexing