i.MX ProcessorsのトピックRe: i.MX8ULP max Display Resolution for MIPI-DSI

i.MX8ULP max Display Resolution for MIPI-DSI

csenatore — Fri, 23 Feb 2024 07:48:31 GMT

I have a question regarding the display resolution of the i.MX8ULP.

What is the maximum display resolution that DCNANO can support via MIPI-DSI?

In Table 568 it says 1080p, and in chapter 66.2 it says 1080p@60.

However, FHD resolutions are not listed in chapter 66.1.

And also the linux driver dcnano-kms.c limits the max framebuffer size to 1280x1280.

Is 1080p therefore possible or not?
And what maximum PixelClk can be implemented via DCNANO?

Re: i.MX8ULP max Display Resolution for MIPI-DSI

joanxie — Sat, 24 Feb 2024 07:22:11 GMT

Max width/height are limited to 1280 on dcnano-kms.c, it can be expanded to 1920.

refer to the dtsi file, this pixel clock is from IMX8ULP_CLK_PLL4_PFD3_DIV2

refer to reference manual, max frequency of PLL4_PFD3_DIV2 is 240Mhz

Re: i.MX8ULP max Display Resolution for MIPI-DSI

WaSt — Mon, 26 Feb 2024 13:22:43 GMT

Hello joanxie,

thank you for your answer.

Then what is the deal with these tables in chapter 66.1 of the reference manual, like this one:

WaSt_0-1708953754217.png

I would interpret that table like the DPI Interface of the display controller is able to output 1024x600 @ 30fps and 800x480 @ 60fps at maximum.

Re: i.MX8ULP max Display Resolution for MIPI-DSI

joanxie — Wed, 28 Feb 2024 08:38:05 GMT

pls refer to the driver dcnano-kms.c as I mentioned before

Re: i.MX8ULP max Display Resolution for MIPI-DSI

WaSt — Wed, 28 Feb 2024 09:01:24 GMT

I have taken a look at it and adjusted it to allow 1920x1080, but that wasn't my question.

My question is about the tables in chapter 66.1 of the reference manual.
Please explain them to me!
As I understand them the DCNANO is not able to output 1920x1080 @ 60fps.

Chapter 66 "LCD Interface (LCDIF/DCNANO)" of the reference manual is pretty confusing in my opinion.
As I understand it the LCDIF and the DCNANO are different display controllers with different capabilites (different linux drivers), and the LCDIF being more powerful than the DCNANO.
But in the RM of the i.MX8ULP there is a lot of references/info/data about the LCDIF, even though the i.MX8ULP doesn't have it. Or am I missing something?

Please clarify the situation for me!
Thank you!

Re: i.MX8ULP max Display Resolution for MIPI-DSI

joanxie — Thu, 29 Feb 2024 08:27:53 GMT

I think I already explain and confirm this, can support 1080p@30,

internal team already verified RM67191 1080P 30 with DPI, for imx8ulp, which supports DCNANO, not lcdif, that's why I said you can refer to the driver, which has been verified on current board, The DRM driver uses the DPU for the i.MX 8QuadMax and i.MX 8QuadXPlus, uses LCDIF for the i.MX 8M
Quad and i.MX 8M Mini, uses DCNANO for the i.MX 8ULP, and uses LCDIFv3 for i.MX 8M Plus and i.MX 93.