RPi4B: an example of what dtdebug=1 in config.txt shows

[Mark Millard]

Turns out there is a debug option for reporting on the
loads of DTBs/DTBOs and such ( dtdebug=1 in config.txt ).
For example, the following reports a:

dtparam: uart0_clkrate=48000000
dtdebug: /__overrides__ has no uart0_clkrate property
"Unknown dtparam 'uart0_clkrate' - ignored"

. . .
MESS:00:00:06.171732:0: dtb_file 'bcm2711-rpi-4-b.dtb'
MESS:00:00:06.173753:0: Trying Device Tree file 'bcm2711-rpi-4-b.dtb'
MESS:00:00:06.186642:0: brfs: File read: /mfs/sd/bcm2711-rpi-4-b.dtb
MESS:00:00:06.189887:0: Loading 'bcm2711-rpi-4-b.dtb' to 0x4000 size 0xb99c
MESS:00:00:06.255822:0: dtdebug: delete_node(/__local_fixups__)
MESS:00:00:06.277110:0: brfs: File read: 47516 bytes
MESS:00:00:06.281513:0: dtdebug: using platform 'bcm2711'
MESS:00:00:06.284083:0: dtdebug: overlay map not loaded
MESS:00:00:06.298583:0: dtdebug: /aliases:i2c_vc=i2c0
MESS:00:00:06.330592:0: dtdebug: /__symbols__:i2c_vc=i2c0
MESS:00:00:06.362273:0: dtdebug: /__overrides__:i2c_vc=i2c0
MESS:00:00:06.425864:0: dtdebug: /__overrides__:i2c_vc_baudrate=i2c0_baudrate
MESS:00:00:06.442254:0: dtdebug: /aliases:i2c=i2c1
MESS:00:00:06.486806:0: dtdebug: /__symbols__:i2c=i2c1
MESS:00:00:06.518905:0: dtdebug: /__overrides__:i2c=i2c1
MESS:00:00:06.533566:0: dtdebug: /aliases:i2c_arm=i2c1
MESS:00:00:06.578548:0: dtdebug: /__symbols__:i2c_arm=i2c1
MESS:00:00:06.611142:0: dtdebug: /__overrides__:i2c_arm=i2c1
MESS:00:00:06.675270:0: dtdebug: /__overrides__:i2c_baudrate=i2c1_baudrate
MESS:00:00:06.740682:0: dtdebug: /__overrides__:i2c_arm_baudrate=i2c1_baudrate
MESS:00:00:06.783605:0: dtparam: uart0_clkrate=48000000
MESS:00:00:06.810402:0: dtdebug: /__overrides__ has no uart0_clkrate property
MESS:00:00:06.814487:0: Unknown dtparam 'uart0_clkrate' - ignored
MESS:00:00:06.822400:0: brfs: File read: /mfs/sd/config.txt
MESS:00:00:06.825716:0: brfs: File read: 268 bytes
MESS:00:00:06.830377:0: dtdebug: Opened overlay file 'overlays/disable-bt.dtbo'
MESS:00:00:06.840220:0: brfs: File read: /mfs/sd/overlays/disable-bt.dtbo
MESS:00:00:06.964366:0: Loaded overlay 'disable-bt'
MESS:00:00:07.035443:0: dtdebug: merge_fragment(/soc/serial at 7e215040,/fragment at 0/__overlay__)
MESS:00:00:07.040906:0: dtdebug:   +prop(status)
MESS:00:00:07.050549:0: dtdebug: merge_fragment() end
MESS:00:00:07.110345:0: dtdebug: merge_fragment(/soc/serial at 7e201000,/fragment at 1/__overlay__)
MESS:00:00:07.115866:0: dtdebug:   +prop(pinctrl-names)
MESS:00:00:07.126576:0: dtdebug:   +prop(pinctrl-0)
MESS:00:00:07.134214:0: dtdebug:   +prop(status)
MESS:00:00:07.141657:0: dtdebug: merge_fragment() end
MESS:00:00:07.202094:0: dtdebug: merge_fragment(/soc/serial at 7e201000/bluetooth,/fragment at 2/__overlay__)
MESS:00:00:07.208447:0: dtdebug:   +prop(status)
MESS:00:00:07.218497:0: dtdebug: merge_fragment() end
MESS:00:00:07.276080:0: dtdebug: merge_fragment(/soc/gpio at 7e200000/uart0_pins,/fragment at 3/__overlay__)
MESS:00:00:07.282378:0: dtdebug:   +prop(brcm,pins)
MESS:00:00:07.292711:0: dtdebug:   +prop(brcm,function)
MESS:00:00:07.300685:0: dtdebug:   +prop(brcm,pull)
MESS:00:00:07.308342:0: dtdebug: merge_fragment() end
MESS:00:00:07.365756:0: dtdebug: merge_fragment(/soc/gpio at 7e200000/bt_pins,/fragment at 4/__overlay__)
MESS:00:00:07.371761:0: dtdebug:   +prop(brcm,pins)
MESS:00:00:07.382181:0: dtdebug:   +prop(brcm,function)
MESS:00:00:07.390161:0: dtdebug:   +prop(brcm,pull)
MESS:00:00:07.397837:0: dtdebug: merge_fragment() end
MESS:00:00:07.400362:0: dtdebug: merge_fragment(/aliases,/fragment at 5/__overlay__)
MESS:00:00:07.407064:0: dtdebug:   +prop(serial0)
MESS:00:00:07.419821:0: dtdebug:   +prop(serial1)
MESS:00:00:07.429872:0: dtdebug: merge_fragment() end
MESS:00:00:07.431938:0: brfs: File read: 1073 bytes
MESS:00:00:07.436768:0: dtdebug: Opened overlay file 'overlays/mmc.dtbo'
MESS:00:00:07.445400:0: brfs: File read: /mfs/sd/overlays/mmc.dtbo
MESS:00:00:07.548017:0: Loaded overlay 'mmc'
MESS:00:00:07.634627:0: dtdebug: merge_fragment(/soc/mmc at 7e300000,/fragment at 0/__overlay__)
MESS:00:00:07.639830:0: dtdebug:   +prop(pinctrl-names)
MESS:00:00:07.648969:0: dtdebug:   +prop(pinctrl-0)
MESS:00:00:07.654982:0: dtdebug:   +prop(bus-width)
MESS:00:00:07.660979:0: dtdebug:   +prop(brcm,overclock-50)
MESS:00:00:07.667633:0: dtdebug:   +prop(status)
MESS:00:00:07.673339:0: dtdebug: merge_fragment() end
MESS:00:00:07.682924:0: dtdebug: merge_fragment(/soc/gpio at 7e200000,/fragment at 1/__overlay__)
MESS:00:00:07.729210:0: dtdebug: merge_fragment(/soc/gpio at 7e200000/mmc_pins,/fragment at 1/__overlay__/mmc_pins)
MESS:00:00:07.736082:0: dtdebug:   +prop(brcm,pins)
MESS:00:00:07.748628:0: dtdebug:   +prop(brcm,function)
MESS:00:00:07.758768:0: dtdebug:   +prop(brcm,pull)
MESS:00:00:07.768616:0: dtdebug:   +prop(phandle)
MESS:00:00:07.778171:0: dtdebug: merge_fragment() end
MESS:00:00:07.780183:0: dtdebug: merge_fragment() end
MESS:00:00:07.844036:0: dtdebug: merge_fragment(/soc/mmc at 7e202000,/fragment at 2/__overlay__)
MESS:00:00:07.849294:0: dtdebug:   +prop(status)
MESS:00:00:07.859282:0: dtdebug: merge_fragment() end
MESS:00:00:07.943119:0: dtdebug: merge_fragment(/soc/mmcnr at 7e300000,/fragment at 3/__overlay__)
MESS:00:00:07.948515:0: dtdebug:   +prop(status)
MESS:00:00:07.956973:0: dtdebug: merge_fragment() end
MESS:00:00:08.009901:0: brfs: File read: 1221 bytes
MESS:00:00:08.012131:0: Failed to open command line file 'cmdline.txt'
MESS:00:00:09.361061:0: dtparam: cam0-pwdn-ctrl=10
MESS:00:00:09.386959:0: dtdebug: found override cam0-pwdn-ctrl
MESS:00:00:09.389727:0: dtparam: cam0-pwdn=5
MESS:00:00:09.417898:0: dtdebug: found override cam0-pwdn
MESS:00:00:09.420235:0: dtparam: arm_freq=2000000000
MESS:00:00:09.449588:0: dtdebug: found override arm_freq
MESS:00:00:09.451834:0: dtparam: core_freq=500000000
MESS:00:00:09.481454:0: dtdebug: /__overrides__ has no core_freq property
MESS:00:00:09.485194:0: Unknown dtparam 'core_freq' - ignored
MESS:00:00:09.590631:0: dtdebug: delete_node(/hat)
. . .

It also reported:

core_freq=500000000
dtdebug: /__overrides__ has no core_freq property
Unknown dtparam 'core_freq' - ignored

This seems to be an indirect effect of having
used arm_freq=2000 in config.txt (as were the
arm_freq=2000000000 related lines in the extraction
above).

I'm not aware that I did anything associated
with the cam0-pwdn related lines: apparently
an automatic adjustment.


===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)