IMX8M plus 1280*800 resolution

[harshth]

Hello,

I have an imx8m plus (pollux) based board from phytec, and a 10.1" LCD display connected to the board.

When the board boots up, the resolution defaults to 1920*1080, which causes the content on the display to be squished(circles are not perfect, oval shaped.). I would like to know how to change the resolution to 1280*800, where I have observed that there isn't any squishing problem. I am able to achieve this working setup by connecting my laptop to the LCD display and pushing the resolution 1280*800.

Any advice would be appreciated, 

Thank you.

Regards

harshth

[malik_cisse]

Did you try to adjust weston configuration?

/etc/xdg/weston/weston.ini
[output]

...
size=1280x720

...

and reboot

[harshth]

Hello Mr.Cisse,

Thank you for quick reply.

yes, I have checked. but this yields the same default resolution. 1920*1080

Please find the list of available modes on my board.

Thank you

UPDATE:

I am able to change the resolution by editing the line "mode" under this section as shown.

[output]
name=HDMI-A-1
mode=1280x720@60

changing the parameter "size" as mentioned still has no effect.

Thank you

[Dhruvit]

Hi @harshth,

I hope you are doing well.

One can also specify resolution in the kernel command line.

video=HDMI-A-1:1280x720@60

As the resolution is changed successfully, Please mark this case as solved.

Thanks & Regards,
Dhruvit Vasavada

[harshth]

Hello Mr.Vasavada,

The resolution has been changed to 1280x720, but I require 1280x800 which is not present in the list of modes when queried. 

Could you please guide me on how to proceed to add this resolution to my board?

Thank you.

Regards
harshth

[Dhruvit · Accepted solution]

Hi @harshth,

i.MX BSP supports few standard modes by default.

For custom resolution, One needs to add a new pixel clock freq entry in samsung_phy_pll_cfg[] at  /drivers/phy/freescale/phy-fsl-samsung-hdmi.c

Please try adding the below entry.

83500000, {
			0x00, 0xD1, 0x68, 0x58, 0x8D, 0x06, 0x00, 0x40,
			0x4F, 0x30, 0x33, 0x65, 0x10, 0x94, 0x24, 0x80,
			0x6C, 0xF2, 0x67, 0x00, 0x10, 0x85, 0x30, 0x3A,
			0x74, 0x8F, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00,
			0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
			0x00, 0xE0, 0x83, 0x0F, 0x3E, 0xF8, 0x00, 0x00,
		},

I hope it helps!

Thanks & Regards,
Dhruvit Vasavada

[harshth]

Hello Mr. Vasavada,

Thank you for your reply.

I have made the changes as mentioned in the appropriate file, additionally I have gone through a few posts in the community related to my request.

1. I have added the 1280*800 resolution in the drm_edid.c file and linked the pixel clock with the same, along with a few other parameters as attached. parameters have been generated by the "cvt" command on ubuntu for 1280*800 resolution. Used the following post as a reference to understand where to add my custom resolution for my IMX8M plus board.
https://community.nxp.com/t5/i-MX-Processors/Supported-resolutions-on-IMX8MQ-via-HDMI/td-p/1005057

2. I have added the pixel clock according to the below link at the device tree level. 
https://developer.toradex.com/linux-bsp/application-development/multimedia/display-output-resolution...

3. After completion of the above steps, the board is unable to render my desired resolution.

Please do let me know if there are any dependencies that I have overlooked.

I would like to know, how do i get my custom resolution to also display when i use the command "cat /sys/class/drm/card1-HDMI-A-1/modes" which displays the list of resolutions supported.

Thank you

[Dhruvit]

Hello @harshth 

I hope you are doing well.

I have a few queries to ask, Please find them below.

Which Linux BSP version you are using?
Please share the LCD part number you are using.
Please share the device tree you are using for i.MX8mp.

These details will help us to narrow down the issue.

Thanks & Regards,

Dhruvit Vasavada

[harshth]

Hello Mr.Vasvada

Apologies for the delayed reply, I am doing good. Thank you, what about you?

Please find the answers to the queries

1. BSP-Yocto-NXP-i.MX8MP-PD22.1.1 phyboard-pollux-imx8mp-2

2. Model Name: T101UWX031H, 
https://www.waveshare.com/wiki/10.1inch_HDMI_LCD_(B)_(with_case)

The board was provided by a client,  I am unable to confirm the part number. Hope these details should be suffcient.

3. imx8mp-phyboard-pollux.dtsi

Please do let me know, if there are any other queries.

Thank you

Regards
Harshth

[Dhruvit]

Hi @harshth,

I have sent you further information over email.

Thanks  & Regards,
Dhruvit Vasavada

[Miles_x]

Hi Dhruvit, 

I have a simliar problem,  use iMX8MP platform, HDMI 1280x800@60HZ output,  please send me the HDMI tool, thanks!

[harshth]

スポイラ

Hello Mr. Vasvada,

Thank you for timely reply, I am able to render the desired resolution on my board.

Thank you,

Regards
Harshth