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Original question:

SN65DSI86: DSI86 Error was reported by the registers, and TX automatic disabled, cause dark screen on Notebook applicati...

SN65DSI86: Blank screen on the display after sometime the system is idle

Manikandan Janakiraman1
Prodigy 110 points
Part Number: SN65DSI86


I am also facing the same problem as in below thread. The display goes blank and its comes back after reboot. DSI side we are not seeing any issue with SoC communication and its only happening at eDP side. Our problem might be looks same as below thread. Can you please share with us the root cause and solution it might be helpful.

Thanks

Mani

  • 0
    TI__Guru**** 179171 points

    Mani

    1. Can you switch to the DSI86 color bar and see if this issue is repeatable? The DSI86 internally generates the color bar and this will help isolate the issue between the DSI side and the eDP side.

    2. When the blank screen happens, could you please dump out registers 0xF0 to 0xF8? Register 0xF8 in particular would indicate an issue with the link training. Sometimes errors flags at register 0xF0 to 0xF3 can be set at power-on or during start of the DSI stream. For this reason, it is recommended to clear flags by writing 0xFF and then reading back status flags.

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    TI__Guru**** 179171 points

    Mani

    I created a FAQ to address this question, please take a look at the FAQ and see if they will help addressing your issue.

    .

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    Prodigy 110 points

    Hi David,

    Thanks for the quick response.

    Here are the register values for when the blank screen error occured.

    0xF0: 0x00

    0xF1: 0x00

    0xF2: 0x00

    0xF3: 0x00

    0xF4: 0x01

    0xF5: 0x20

    0xF6: 0x42

    0xF7: 0x00

    0xF8: 0x01

    When the error occurred, I have enabled the color bar and it has been displayed on the panel so it seems like eDP link is working and DSI link is broken. Now I am working on collecting data from SoC  for DSI link  when the error occurred to debug further. Let me know if you have any recommendation to fix DSI link.

    Thanks

    Mani

  • 0 in reply to Manikandan Janakiraman1
    TI__Guru**** 179171 points

    Mani

    Error at register 0xF6 indicates errors associated with DSI to DP video timing. Typically, errors are set in these registers when video timing programmed into DSI86 doesn’t match timing received on the DSI interface. 

    You can use this spreadsheet to check the video timing programming registers at 0x20 thru 0x3A.

    .

    Thanks
    David

  • 0 in reply to David (ASIC) Liu
    Prodigy 110 points

    Hi David, Thanks for the Info. Our SW team understand the problem now and they working on the fix. 

  • 0 in reply to David (ASIC) Liu
    Prodigy 110 points

    Hi David,

    We are having another problem with one of our edp display which is using SN65DSI86 bridge chip. We don't know whether the problem is because of the bridge chip or the display. The problem is that the vertical color bar appears on top of the screen content (refer the attachment)  and this only can be fixed by restarting the entire system. The problem is hard to replicate again for debugging and so far we had two reports on this vertical color bar problem. Please let me know if you have seen this issue before with your experience and let us know your suggestion which might caused this problem. Unfortunately we don't have edp chip register details while the problem happened, Thanks Thanks

    Mani

  • 0 in reply to Manikandan Janakiraman1
    TI__Guru**** 179171 points

    Mani

    Are you seeing this issue when the color bar is enabled in DSI86? If you don't see the issue with the color bar, then I believe the issue comes from the DSI source since the DSI86 just passed the data from the DSI side to the eDP side.

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    Prodigy 110 points

    Hi David,

    No. We haven't enabled the color bar and also the color bar width is not matching with edp bridge generated color bar width. So it might be from the DSI source. Let me collect more data when the problem occurs.

    Thanks

    Mani

  • 0 in reply to Manikandan Janakiraman1
    TI__Guru**** 179171 points

    Mani

    Sounds good, is the video source sending both the color bar and the normal content? The DSI86 passes along the input video being received at the DSI side and will not insert video at the eDP side. If the video source is sending both the color bar and the normal content, you may need to check the VSYNC programmed value.

    Thanks

    David