Can't enable uart for Ubuntu SOS


        We have a development board with i5-7300U and tried to install acrn sos. We generated the board and scenario xmls using ACRN Configuration Tool, builded the acrn Hypervisor with RELEASE=0. When boot into ubuntu-service-vm, the system got stuck with HDMI show "loading ACRN..."
        There is a serial port on the board, so we want to output the boot log. The setting of the uart is as fellows. The serial works ok when boot into the Ubuntu without acrn kernel(native boot?) ; but there is nothing output when boot into  ubuntu-service-vm.  Is this configuration correct? or should I do something else?

$ dmesg | grep tty
[   13.399735] dw-apb-uart.2: ttyS4 at MMIO 0xb151b000 (irq = 20, base_baud = 115200) is a 16550A
[   13.399769] printk: console [ttyS4] enabled

$ vi /etc/grub.d/40_custom
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry "ACRN Multiboot Ubuntu Service VM" --id ubuntu-service-vm {
  insmod gzio
  insmod part_gpt
  insmod ext2

  search --no-floppy --fs-uuid --set 9efd748b-88fc-4082-b2f9-2e91b6e3dc07
  echo 'loading ACRN...'
  multiboot2 /boot/acrn/acrn.bin  root=PARTUUID="41d2eeec-fd7b-4479-9ae0-3a41845d25ff" uart=mmio@0xb151b000
  module2 /boot/bzImage Linux_bzImage

Best Regards

Xi'an R&D Center Computerized Numerical Control R&D Dept.  Shuai Zhang 
Tel : 029-84503040-8360 
E-mail :  zhangshuai@...     Web :

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