iMX8 HDMI display problem

[system-link]

Hello! I have a problem with connect HDMI display with not standard resolution 1024x600. I spent a lot of time for running this display om iMX8, and get it by editing imx_hdp.c file and define "no_edid" option. Kernel 4.19.35. I include this info, that get from cvt tool. 

static struct drm_display_mode edid_cea_modes[] = {
	/* 2 - 1024x600@60Hz */
	{ DRM_MODE("1024x600", DRM_MODE_TYPE_DRIVER, 54000, 1024, 1072,
		   1168, 1312, 0, 600, 603, 613, 626, 0,
		   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC),
	  .vrefresh = 66, .picture_aspect_ratio = HDMI_PICTURE_ASPECT_16_9, },

After this I get working display, but on the left of screen I see pink line about 2 pixel. 

I try correct modeline, but can't move picture on display. This display normaly work on iMX6 processor with this params:

But, when I try use this params (with correction clock to 54 MHz) in kernel - display work with artefact.

Maybe is another way move screen in kernel files?

 

[igorpadykov]

Hi system-link

one can try suggestions provided for i.MX8 on

https://developer.toradex.com/knowledge-base/display-output-resolution-and-timings-linux

Best regards
igor

[system-link]

Hi Igor.

Unfortunelly this info not helpfull for my problem. 

Very interesting, but when I try connect HDMI from iMX8 to my desktop monitor 1920x1080 with same modeline as for 1024x600, I also see this pink line. I think that error produced inside of kernel...

 

[igorpadykov]

what "kernel" used in the case, suggest to try ones from nxp

source.codeaurora.org/external/imx/linux-imx repository :
https://source.codeaurora.org/external/imx/linux-imx/tree/?h=imx_5.4.47_2.2.0

Test on NXP MEK reference board with Demo Images from

https://www.nxp.com/design/software/embedded-software/i-mx-software/embedded-linux-for-i-mx-applicat...

Best regards
igor

[system-link]

Hello!

In Variscite sources there are no 5.4 kernel for Debian, that I need. But I tried install kernel 5.4 with Yocto. And I get new problem of work with my HDMI monitor. I wanted insert modeline for 1024x600 HDMI display to file imx_hdp.c, how I do in kernel 4.9, but there are not this file in new kernel.

If I use clean kerenel, HDMI monitor also don't work. I get this info:

[    1.413813] [drm:cdns_hdmi_get_edid_block] *ERROR* get block[0] edid failed: -22
[    1.421224] [drm:cdns_hdmi_connector_get_modes] *ERROR* Invalid edid
[    1.427690] [drm] Cannot find any crtc or sizes

How I can run HDMI 1024*600 on kernel 5.4?

[igorpadykov]

>How I can run HDMI 1024*600 on kernel 5.4?

there is no guaranteed solution for non-standard hdmi resolutions.

" kernel 5.4" is supported in nxp bsps from  official source.codeaurora.org/external/imx/linux-imx repository

https://source.codeaurora.org/external/imx/linux-imx/tree/?h=imx_5.4.47_2.2.0

Third parties bsps and software are not supported by nxp, suggest to apply to variscite support

for additional help.

Best regards
igor

[system-link]

It's very bad news... I don't uderstand, why iMX8 don't support non standard HDMI resolution. iMX6 without any problem work with this display.