search

bootlin / buildroot-external-st

External Buildroot tree for STMicroelectronics boards configurations
56 stars 28 forks source link

Suspend-to-RAM broken: Instead of resuming properly, the device reboots #60

Closed DrTobe closed 1 month ago

DrTobe commented 1 month ago

Instead of resuming where the system left off before suspending, the device does a full reboot. This has been tested with the pre-built images for the DK and the DK2 board.

Steps to reproduce:

  1. Download the image, flash the SD card, boot the system
  2. echo deep > /sys/power/mem_sleep
  3. echo +20 > /sys/class/rtc/rtc0/wakealarm
  4. echo mem > /sys/power/state
  5. Wait 20 seconds, the system reboots instead of resuming

I initally observed this on an STM32MP157C-DK2 board (157C, not 157F which I do not have available). To verify that behaviour on the exact reference hardware, I tested this on the STM32MP135F-DK, too. It shows the same behaviour so I suppose this may be true for all setups.

If you need any more information or if I should do some additional testing, please let me know.

kmaincent commented 1 month ago

Hello, thanks for reporting the issue. The problem comes from using STM32MP_USB_PROGRAMMER build option in TF-A. Indeed using this option disabled the power features to avoid oversized image. We will need a dedicated TF-A image for flashing also on stm32mp1 then. I will update the branch.

DrTobe commented 1 month ago

Incredible, just removing STM32MP_USB_PROGRAMMER=1 from the additional TF-A build variables fixes the suspend-to-RAM mode.

Thank you so so so so much!