How to fix the default HDMI resolution


How to fix the default HDMI resolution

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Contributor II

When my mx6 quad board has a HDMI monitor connected, the unit powers up fine with no display problems.

Resolution set to 1280x720@60.

If I power the board with the monitor disconnected, then plug it in after boot the resolution seems to set to 640x480.

My application requires that the resolution should atleast default to 1280x720 or even higher.

So, can I fix the resolution to a set value no matter what  monitor or when a monitor is connected?

In other words - override auto detection and always have the same fixed resolution.

thanks guys,


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Contributor III

I recently changed mine in barebox:

Interrupt the boot.

type "nv"video=HDMI-A-1:1280x800-24"


then reboot.

This successfully changed the mode as displayed with fbset command (although it resulted in the projector that I'm driving displaying a blank screen, so not a fix for me.) Please change the numbers as appropriate for your situation. The format appears to be correct.

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Contributor II

Hi again Igor, I should have been a bit clearer on my issue.

**With Monitor disconnected**

Early on during the U-boot process this message is output to the console

>No panel detected: default to HDMI

>Display: HDMI (1024x768)

and it is infact as you said, part of display_info_t const displays[] = {{

in my case in wandboard.c so I can change that no problem.

But later during the kernel boot process this comes up

>fbcvt: 1920x1080@60: CVT Name - 2.073M9

>mxc_sdc_fb fb.28: registered mxc display driver hdmi

>mxc_sdc_fb fb.28: 1920x1080 h_sync,r,l: 44,528,148  v_sync,l,u: 5,4,36 pixclock=148500000 Hz

I have now fixed this too to be correctly set at 1280x720@60 so no problem there.

Now, perhaps I should have been a bit clearer on this -

The boot process continues and finally Android comes up.

Then if I plug my monitor in this is output

>root@wandboard:/ # mxc_sdc_fb fb.28: 640x480 h_sync,r,l: 96,16,48  v_sync,l,u: 2,10,33 pixclock=25175000 Hz

>mxc_sdc_fb fb.28: 640x480 h_sync,r,l: 96,16,48  v_sync,l,u: 2,10,33 pixclock=25200000 Hz

So this is where I am bogged down, trying to find where this is set.

Thanks again


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Contributor II

I tried that Igor and no good.

any other ideas?

the board is a wandboard quad.

thanks William

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Contributor II

Thanks very much Igor, I will give it a try and let you know.

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NXP TechSupport
NXP TechSupport

Hi William

one can try to change it in uboot/..mx6sabresd/mx6sabresd.c,

struct display_info_t const displays[]

uboot-imx.git - Freescale i.MX u-boot Tree

Best regards



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