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TRDX-3P-AQUILA-AM69: Using DP at 4k@60fps Resolution

Max Krummenacher
Prodigy 30 points
Part Number: TRDX-3P-AQUILA-AM69
Other Parts Discussed in Thread: AM69

Tool/software:

Hi

I would like to enable 4k60fps resolution on a configured DP output.

Currently I have the equivalent of commit [1] in the device tree which limits the lane bandwidth to 2700 Mbps which then leads to 4k@60fps filtered out of the list of possible modes.

I tried to increase in the device tree the lane bandwidth to 5400 Mbps which results in a working 4k@60fps on the one setup I tested. No warning or error messages related to the DP link are in the kernel output.

Is commit [1] possibly over cautious or only needed for the AM69-EVK HW and its save to allow 5400 Mbps or with the 'right' device/monitor combination I will run into issues?

Regards

Max

[1] git.ti.com/.../k3-j784s4-evm.dts

  • 0
    TI__Guru 51823 points

    Hi Max,

    Is this using the MHDP PHY? There was a known issue where SYNC LOST was seen at 4K 60FPS specifically with the MHDP PHY back in 8.6 SDK. 2K resolution we saw was consistently stable, so we limited the bandwidth to 2700Mbps.

    I am not aware of any improvements done from TI side for this issue, so any fixes would most likely be from upstream community. 

    Regards,

    Takuma 

  • 0 in reply to Takuma Fujiwara
    Intellectual 685 points

     - Can you describe how to reproduce the issue you had, so we can try to run similar tests on our side to confirm if this is working correctly or not now?

     - I would have a request for TI to officially support 4k@60fps DP on AM69, can you consider this request and let me know?

  • 0 in reply to fd
    Prodigy 30 points

    Hi

    > Is this using the MHDP PHY?

    I think yes. We are using SERDES4 together with the DP AUX channel of the AM69. I.e. the same connections as used on the AM69 EVM.

    Regards

    Max

  • 0 in reply to Max Krummenacher
    TI__Guru 51823 points

    Hi Fd, Max,

    The issue was seen for most, if not all, 4K displays running at 60 frames. The issue manifests itself as a continuous stream of "CRTC SYNC LOST" logs on the main terminal, although display shows 4K resolution.

    In any case, I have opened up an internal Jira to see if folks on the SDK team can revisit this and whether they are aware of any changes. 

    Regards,

    Takuma