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AM625: How to Dual Display Same Content Simultaneously

Kevin Peng
Expert 4888 points

Part Number: AM625
Other Parts Discussed in Thread: SK-AM62B

Hi TI Experts,

Customer is working on our SK-AM62B with latest SDK.

Customer is looking to implement dual-screen mirroring on an AM62x platform.


By “dual-screen mirroring,” customer means the ability to run a single application and have its display output appear simultaneously on two screens (i.e., outputting to both the RGB and LVDS interfaces at the same time).


In customer's experiments with SK‑AM62B board, customer found that while it does support a "dual-screen configuration", but it operates in an “extended desktop” mode—similar to Windows’ extended display mode. Which means that the content is showing only on one screen firstly and customer has to need manually use the mouse to drag the content into the other screen to achieve "dual display"

Customer wants to know if we have a solution or guidance that could teach customer how to achieve a dual display (RGB+LVDS) simultaneously showing the same content without the need of using the mouse to drag the contents.

Thanks,

Kevin

  • 0
    TI__Genius 15740 points

    Hi Kevin,
    If the ask is for the DSS to clone the input framebuffer to the 2 VPs, that is not possible. You will need to copy the framebuffer and feed it to the second video pipeline in order get get a cloned display between DPI and OLDI. Or you can easily get a cloned display by using 2 single link OLDI panels, but for DPI cloning, you'll need software modification.

  • 0 in reply to Divyansh Mittal
    TI__Expert 4888 points

    Hi Divyansh,

    Thanks for the reply!

    It is fine to copy the framebuffer & feed to the second video pipeline, customer is okay with this workaround.

    Based on the latest SDK, could you help summarize a guidance what are the modifications needed for customer to achieve it please?

    Thanks,

    Kevin 

  • 0 in reply to Kevin Peng
    TI__Genius 15740 points

    Hi Kevin, 
    This will have to be a userspace application workaround, I am reassigning the thread to the concerned expert for their inputs.

  • 0 in reply to Divyansh Mittal
    TI__Intellectual 2040 points

    Hi Kevin, 

    We are looking into it and doing some testing on our end. We will get back to you sometime next week with results. 

    Regards,

    Shriya

  • 0 in reply to Shriya Surti
    TI__Expert 4888 points

    Hi Shriya,

    Thanks for the support, please note customer is also okay with using Weston to achieve this. However, customer needs an example so that they could simply try on our EVM using the default latest SDK.

    Thanks,

    Kevin

  • +1 in reply to Kevin Peng
    TI__Intellectual 2040 points

    Hey Kevin,

    Are both displays the same resolution? On our end we modified the following file to support both an HDMI and LVDS display (no RGB display available):

    ./etc/xdg/weston/weston.ini

    within this file we appended the following code to the end of the existing file: 

    [output]
name=LVDS-1

[output]
name=HDMI-A-1
same-as=LVDS-1

    However, these displays are not the same resolution. After talking to our software dev team, both displays should have the same resolution in order to be able to duplicate the display. Please let us know if these modifications work on your end. 

    Regards,

    Shriya 

  • 0 in reply to Shriya Surti
    TI__Expert 4888 points

    Hi Shriya,

    Thanks for the feedback, please see customer's block diagram below, for both LVDS -> EDP & RGB -> HDMI, customer are using 1080P 30FPS with the same resolution, I will let customer have a try for your solution and get back.

    Thanks,

    Kevin

  • 0 in reply to Shriya Surti
    TI__Expert 4888 points

    Hi Shriya,

    Thanks for the support, customer has an additional question based on it, with all the conditions the same (LVDS 1080p 30fps, HDMI 1080p 30 fps), if customer wants both of the display show the contents individually (not the same) , will the change looks like below:

    ./etc/xdg/weston/weston.ini 

    [output]
name=LVDS-1

[output]
name=HDMI-A-1

    Thanks,

    Kevin

  • +1 in reply to Kevin Peng
    TI__Intellectual 2040 points

    Hi Kevin,

    By default, weston supports extending displays. No changes to weston.ini are necessary, as weston will automatically show up on both displays.

    Regards,

    Shriya