disable edid (hdmi, rgb video output)

There's two uEnv.txt's for compatibility with old eMMC's..

/uEnv.txt -> /boot/uEnv.txt

HOWEVER, /uEnv.txt doesn't have the features of /boot/uEnv.txt

So make sure your uEnv.txt is found in /boot/uEnv.txt

Otherwise your /boot/uEnv.txt looks fine..

Regards

ok. now please find below the uEnv.txt directly from /boot (not from rootfs…)! but it don’t work although

#Docs: http://elinux.org/Beagleboard:U-boot_partitioning_layout_3.0

uname_r=4.1.15-ti-rt-r43
#uuid=
#dtb=

##BeagleBone Black/Green dtb’s for v4.1.x (BeagleBone White just works…)

##BeagleBone Black: HDMI (Audio/Video) disabled:
#dtb=am335x-boneblack-emmc-overlay.dtb

##BeagleBone Black: eMMC disabled:
#dtb=am335x-boneblack-hdmi-overlay.dtb

##BeagleBone Black: HDMI Audio/eMMC disabled:
#dtb=am335x-boneblack-nhdmi-overlay.dtb

##BeagleBone Black: HDMI (Audio/Video)/eMMC disabled:
#dtb=am335x-boneblack-overlay.dtb

##BeagleBone Black: wl1835
#dtb=am335x-boneblack-wl1835mod.dtb

##BeagleBone Green: eMMC disabled
#dtb=am335x-bonegreen-overlay.dtb

cmdline=coherent_pool=1M quiet cape_universal=enable

#In the event of edid real failures, uncomment this next line:
cmdline=coherent_pool=1M quiet cape_universal=enable video=HDMI-A-1:x800@400e

##Example v3.8.x
#cape_disable=capemgr.disable_partno=
#cape_enable=capemgr.enable_partno=

##Example v4.1.x
#cape_disable=bone_capemgr.disable_partno=
#cape_enable=bone_capemgr.enable_partno=

##Disable HDMI/eMMC (v3.8.x)
#cape_disable=capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN,BB-BONE-EMMC-2G

##Disable HDMI (v3.8.x)
#cape_disable=capemgr.disable_partno=BB-BONELT-HDMI,BB-BONELT-HDMIN

##Disable eMMC (v3.8.x)
#cape_disable=capemgr.disable_partno=BB-BONE-EMMC-2G

##Audio Cape (needs HDMI Audio disabled) (v3.8.x)
#cape_disable=capemgr.disable_partno=BB-BONELT-HDMI
#cape_enable=capemgr.enable_partno=BB-BONE-AUDI-02

##enable Generic eMMC Flasher:

^ only have one "cmdline=" u-boot doesn't always pick the one you want
when you have two variables..

Regards,

ok. thank, it works :slight_smile: failure was two command line, and the cmdline from the uEnv.txt at /boot was still wrong, below the correct:

#In the event of edid real failures, uncomment this next line:
cmdline=coherent_pool=1M quiet video=HDMI-A-1:800x480M@60e cape_universal=disable init=/lib/systemd/systemd

so now i am really interested if resolution like 1920x720 or 320x240 also works… maybe anyone still know this?

You should be able to craft any resolution within the frequency range
of the AM335x LCD pixel clock. Very low resolutions (like 320x240)
may encounter problems since they require pixel doubling in the HDMI
framer to keep the HDMI clock within it's legal range. The driver
should handle this properly, but the code path is probably not tested
a bunch for HDMI (you'd typically connect a low-resolution LCD like
that directly rather than via HDMI).

Just try it and see.

it seems that 320x240 is not working? what is the reason? it’s to low? and how can i access now this resolution? thanks

so because cmdline does not work with qvga i must study the variant with following link:
https://github.com/beagleboard/bb.org-overlays/blob/master/src/arm/BB-BONE-LCD7-01-00A1.dts#L230

does anyone know, if I can see also a result on the hdmi-output with that, or does I disable the hdmi-output with that?

thanks