Can't output log in qemu windows,but log can ouput with -serial option


#1

I have a problem when using qemu-system-arm now.
When I using below cmd:
qemu-system-arm -M vexpress-a9 -m 256M -kernel /home/an/linux_workspace/linux-3.4.4/arch/arm/boot/zImage -append “root=/dev/mmcblk0 rw console=ttyAMA0 console=serial0 init=/linuxrc” -sd /home/an/linux_workspace/rootfs.img -serial file:/tmp/serial.out -dtb /home/an/linux_workspace/linux-3.4.4/arch/arm/boot/vexpress-v2p-ca9.dtb
I can get the log from file:/tmp/serial.out(or get the log by option:-serial stdio), the system boot up successfully, but in my QEMU windows, I can’t see any output but black screen.

Before I use the dtb option, it all works well with below cmd:
qemu-system-arm -M vexpress-a9 -m 256M -kernel /home/an/linux_workspace/linux-3.4.4/arch/arm/boot/zImage -append “root=/dev/mmcblk0 rw console=ttyAMA0 console=tty0 init=/linuxrc” -sd /home/an/linux_workspace/rootfs.img -serial file:/tmp/serial.out

I guess it is the configuration issue with serial port, but I have no idea how to configure it.
In vexpress-v2p-ca9.dts, the infor related serial as below:
aliases {
serial0 = &v2m_serial0;
serial1 = &v2m_serial1;
serial2 = &v2m_serial2;
serial3 = &v2m_serial3;
i2c0 = &v2m_i2c_dvi;
i2c1 = &v2m_i2c_pcie;
};

Is there any suggestion to help me to get output in QEMU window?
It will be greatly appreciated if you can give me some advice, thanks a lot.