AI-64 c66x c7x R5 turning off the A72 companions

hey every one !
is there a way beyond the “no share memory dts” to just turn them of easily (C66x C7x R5)
because even with booting with the device tree configuration im still using more than 7 watts
when linux is turned off … or I must dig in the TI reference manual and switch off the right register with memory mapping that’s a lot of pages there?
J721E DRA829/TDA4VM/AM752x Processors Silicon Revision 1.0 Technical Reference Manual
extract from the linked document:

0. The device is partitioned into three functional domains, each containing specific processing cores and peripherals:

** * Wake-up (WKUP) domain**
** * Microcontroller (MCU) domain**
** * MAIN domainThis domain fragmentation enables the device to achieve lower power dissipation profiles by allowing the power supplies to unused domains to be completely turned off and allows efficient addressing of safety requirements.**

regards Julien.

The device tree specifies the firmware image to load, and my experience has been that (at least the R5 cores) claim to be off on startup if they aren’t loaded with firmware. If you check their status, are they on? You can cat /sys/class/remoteproc/remoteproc*/{state,name} to check.

I would expect the “no shared memory” version to avoid specifying any firmware and thus leave them off. Is that not the case?

You can also echo stop or whatever the value is to that state attribute to turn off a running remoteproc core.

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Hey thanks for answering @kaelinl
it’s appear that everything is offline ( with the device tree “no shared memory” )
but I have not seen any significant power consumption reduced…
and mostly, when I do a soft shut down with the PWR button on board
once linux is completely off, I’m still at 7.78 watts where this current draw may come from ?
is there something polling in the back ground ?
I feel like I missing something … I m not quite alright with that…

main.c (2.3 KB)

Mean while 20 watts it’s only 30 euros/year at 24h a day but understanding what’s going on would be a good things…
but perhaps not so many can tell it’s a peace of tech that we have there :wink: