Linux/TDA2EVM5777: Display handling in A15 for VSDK-Linux

prabhuraj tavag20

Expert 2020 points

Part Number: TDA2EVM5777

Tool/software: Linux

Hi all,

I am working on VSDK 3.02 - Linux. Here, the display architecture is based on Links and chains framework. If I need to display something on HDMI, then A15 will trigger the M4, then M4 takes over the control and handles the display. PDK, running in M4 side will have display drivers and is used to handle the same.

I want to understand how the display control triggering/handling is taken care from A15 side.

For example, in Processor SDK-Linux, omapdrm driver handles the complete display mechanism on A15.

In the Linux 4.4.84, I see,

drivers/gpu/drm/omapdrm - used for PSDK-Linux display handling

Similarly, which part of the driver in VSDK-Linux 3.02 on A15 side, is used to trigger/initialize the M4 through IPC?

Please let me know.

thanks and regards,

prabhuraj

over 8 years ago

0 Yordan Kamenov over 8 years ago

TI__Mastermind 42515 points

Hi Prabhuraj,

I have forwarded your question to VisionSDK experts.

Regards,
Yordan

0 Shiju Sivasankaran over 8 years ago in reply to Yordan Kamenov

TI__Genius 13395 points

For M4 side display in place, no A15 side logic required to trigger the display, no omap drm counter part here. A15 side link just act as a memory to memory mode, where it is just like a processing node and output frame are written in memory. This link normally connects to display link on M4 via a pair of IPC links to export the frames from A15 to M4. Now the display link sends these frame to DSS HW using PDK drivers. Please note that there is no frame copy in any place in the data path/chain.

regards, Shiju

0 prabhuraj tavag20 over 8 years ago in reply to Shiju Sivasankaran

Expert 2020 points

Thanks Shiju for your insights.

So, if I have to replace omapdrm with display driven through links and chains then no changes are needed on Linux side?

thanks,

prabhuraj

0 Shiju Sivasankaran over 8 years ago in reply to prabhuraj tavag20

TI__Genius 13395 points

Prabhuraj
If you are using vision SDK Linux (preferably the latest version - VSDK 3.2 release) , you do not need any change in Linux side, we have taken care all to support HDMI display from M4 side along with A15 running Linux

regards, Shiju

0 prabhuraj tavag20 over 8 years ago in reply to Shiju Sivasankaran

Expert 2020 points

Thanks Shiju.

Our usecase is such that, we want to display the Android display through M4. Currently Android display is handled through OMAPDRM. I am looking to replace it. We are using Robust RVC. TI released Robust RVC comes with VSDK 2-12. We have ported it to the latest VSDK 3-02.

First, to get this working on EVK, I understand that, we need not do any modifications in links framework and PDK.

Please provide your valuable insights regarding this.

Thanks,
Prabhuraj

0 Shiju Sivasankaran over 8 years ago in reply to prabhuraj tavag20

TI__Genius 13395 points

Prabhuraj

Need to check with our Robust RVC team if we can forsee any issues , unfortunately the main engineer is on vacation till 7th May, will conform once he is back in office

Regards, Shiju

0 prabhuraj tavag20 over 8 years ago in reply to Shiju Sivasankaran

Expert 2020 points

Thanks Shiju. We communicated with Robust RVC team from TI previously. What we understood from them is, there should not be any issues to drive Android display through M4.

To start with, I am looking to just write an application which will read a JPEG/PNG image in Android root prompt and display it through M4 using links and chains.
As getting in touch with main engineer is long time from now (7th May), can you give basic pointers to get started?

thanks,
prabhuraj

0 Shiju Sivasankaran over 8 years ago in reply to prabhuraj tavag20

TI__Genius 13395 points

prabhuraj

Sorry, it was a typo, He will be available on 7th March.

Please request a sample chain below from RVC/Android team

NullSrc (read from SD card) on A15 -> Decode -> Display on M4 on Android

regards, Shiju

0 Chetan Matad over 8 years ago in reply to prabhuraj tavag20

TI__Expert 3970 points

Hi Prabhuraj ,

You can look at the usecase null_src_decode_display ,

Here we read a frame / file from A15 decode the same using iva in m4 and do a m4 display .

Regards
Chetan.M

0 prabhuraj tavag20 over 8 years ago in reply to Chetan Matad

Expert 2020 points

Thanks Shiju and Chetan.

Regards,

Prabhuraj

0 Shiju Sivasankaran over 8 years ago in reply to prabhuraj tavag20

TI__Genius 13395 points

thanks

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Linux/TDA2EVM5777: Display handling in A15 for VSDK-Linux