1280x800 resolution support in Xavier NX eDP

Hi,

We are designing a custom carrier board with Xavier NX module and we are planning to add 1280x800 LVDS display. The LVDS display is connected to Xavier NX eDP port via an eDP-to-LVDS bridge (PTN3460).

The display panel does not have an EDID ROM, and but the bridge IC has the support to add custom EDID values and we will flash the EDID for 1280x800 resolution in the bridge.

Can you please tell us whether the 1280x800 resolution via eDP is supported in Xavier NX (BSP 32.4.2)?

Hi,

It should work but we don’t officially verify eDP on NX.

You could refer to tegra186-quill-p3310-1000-c00-00-auo-1080p-edp.dts which is a TX2 dts file first and write a similar one for NX.

Please note that eDP driver still reads EDID, so if there is no EDID rom on your panel, you need to hack one in driver.
https://elinux.org/Jetson_TX2/r28_Display_debug

Thanks for the quick reply @WayneWWW.
we can add the EDID the in the driver.

Our concern is that 1280x800 is not a standard resolution, we would like to know whether this resolution will be support by Xavier NX processor without any issues.

Hi,

We cannot tell whether this mode is supported by just the info of x and y resolution. Display mode has other parameters like Horizontal/Vertical back porch and front porch. Our display driver has a calculation to filter them.

It does not mean common modes would definitely be supported. For example, many users here asking about why their 4k mode cannot work? Isn’t 4k a common mode? Yes, of course it is.
But unfortunately the detail timing in this 4k mode cannot pass the calculation so it still not supports.

Thanks, @WayneWWW.

I am not sure this would help, but we have the display timings for the LCD panel,

Our display driver has a calculation to filter them.

Is it possible to tell us whether the NX will support these timing parameters? The thing is we are designing a custom carrier board, we are looking for some assurance that this display will work on our carrier board.

Also please share if you know any other way to confirm this other than testing with the actual carrier board.

Cheers.

Hi,

Sorry that I won’t help you do the calculation here. But you could refer to the driver code. Please download the kernel src from dlc.

/kernel/nvidia/drivers/video/tegra/dc/dp.c
-> tegra_dp_mode_filter

/kernel/nvidia/drivers/video/tegra/dc/mode.c
->check_nvdisp_mode_timings