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Original question:

Linux/AM3354: 1366x768 24-bit LCD issue

AM4376: DSS 1366x768 resolution support

Tony Tang
Mastermind 30522 points

Part Number: AM4376

From below post, width should be multiple of 16, is it true?  I didn't see such limitation on TRM or SDK user guide: 

https://e2e.ti.com/support/processors/f/791/t/659517

My customer wants to use 1366*768, have problem on it. below post resolution is the right way?

https://e2e.ti.com/support/processors/f/791/p/157746/1049056#1049056

  • 0
    TI__Guru** 109890 points

    Hello Tony,

    Our graphics expert is on vacation for the next two weeks. Let me poke around and see if I can find any information for you.

    Regards,

    Nick

  • 0 in reply to Nick Saulnier
    TI__Guru** 109890 points

    Hello Tony,

    AM437x DSS needs the width to be divisible by 8, so 1366 is not supported.

     Regards,

    Nick

  • 0 in reply to Nick Saulnier
    TI__Mastermind 30522 points

    Nick,

    Thanks. would you please point out where defined the 8x requirement? 

    Can it be workaround? configure to 1368 line size and fill valid content within 1366?

  • 0 in reply to Tony Tang
    TI__Guru** 109890 points

    Hello Tony,

    It does not look like it is highlighted in the TRM - I filed a request to update the DSS chapter in the next TRM release, but I do not know when that will be. It is mentioned in the register description for DISPC_SIZE_LCD.

    It sounds like the display driver would present a display of 1368 up to the Linux applications, so it would be the responsibility of the application to only use 1366 pixels per line.

    The display driver will also push 1368 pixels per line out to the LCD. It does not sound like there is a generic workaround, because different LCD models might do different things when they receive too many pixels per line. e.g., maybe the LCD discards the extra pixels. Maybe the LCD puts those extra pixels at the beginning of the same line, or at the beginning of the next line. etc.

    Regards,

    Nick

  • 0 in reply to Nick Saulnier
    TI__Mastermind 30522 points

    Nick,

    Thanks for the details.

    as selected eDP interface  LCD, so added a device NCS8801 to convert RGB888 to eDP. AM437x output 1368 to NCS8801, NCS8051 output 1366 to LCD, it result in color mess on display.

    seems there no method to workaround it for customer to adopt this LCD.