278f908d55
The current Buildroot defconfigs for qemu_x86 and qemu_x86_64
instantiate a console on tty1, which appears on QEMU's
graphical window. Add a console on the serial port (ttyS0) to
be used later for gitlab testing.
This change is need since the script used for gitlab testing
needs to use a serial output with pexpect.
This change is similar to the one made for raspberrypi [1] to
handle HDMI and serial console:
This requires three changes:
1. have two 'console=' entries in the kernel command line: tty1,
then ttyS0;
2. change BR2_TARGET_GENERIC_GETTY_PORT to "console", so it starts
a getty on the last console= passed to the kernel, ttyS0;
3. add a new getty on tty1 to the generated inittab.
Step 2 is actually obtained by removing BR2_TARGET_GENERIC_GETTY_PORT
entirely from the defconfigs, since "console" is the default value.
Step 3 requires a post-build script since the Buildroot makefiles can
configure only one console.
Note: instead of simply adding a new getty on ttyS0 (which would
work) this patch actually changes BR2_TARGET_GENERIC_GETTY_PORT to
instantiate a console on UART, then adds back tty1 via
post-build.sh. This is done only to avoid the "GENERIC_SERIAL" comment
where we instantiate a console on QEMU graphical window, then
instantiate a really-serial console on another line.
The result is these two inittab lines:
console::respawn:/sbin/getty -L console 0 vt100 # GENERIC_SERIAL
tty1::respawn:/sbin/getty -L tty1 0 vt100 # QEMU graphical window
[1]
|
||
|---|---|---|
| .. | ||
| linux.config | ||
| post-build.sh | ||
| readme.txt | ||
Run the emulation with: qemu-system-i386 -M pc -kernel output/images/bzImage -drive file=output/images/rootfs.ext2,if=virtio,format=raw -append "rootwait root=/dev/vda console=tty1 console=ttyS0" -serial stdio -net nic,model=virtio -net user Optionally add -smp N to emulate a SMP system with N CPUs. The login prompt will appear in the graphical window. Tested with QEMU 2.12.0