STM32MP153 freezes at suspend when DMA buffers are allocated with stm32_rpmsg_sdb

[atessadri]

Hi all,

   I work on a STM32MP153 device and I used the command echo mem > /sys/power/state to put CPU A7 in Cstop mode, but I still have MCU running.

Before to enter suspend mode I have shared some memory buffers with MCU M4 with virtio RPMSG (as recommended).

In such case the suspend procedure doesn't come to end and it freezes in the middle.

If DMA buffers are not allocated everything works.

I have stopped every write operation from MCU M4 to don't interfere with the suspend process, but it freezes as well.

Thank you in advance

   Andrea

[atessadri]

With no_console_suspend I have been able to see that the suspend procedure is completed (so my assumption was wrong).

There is an issue in the coprocessor code preventing it to reach the point where it will wake-up Linux again.

So, it isn't related to DMA buffers allocation/deallocation.

  Andrea