Re: [Qemu-discuss] Emulated Raspberry Pi kernel panic - can't set up serial port?

[Peter Maydell]

On 17 December 2017 at 05:57, Adam Baxter <address@hidden> wrote:
> Hi,
> I realise this isn't strictly a qemu issue but I can't find any reference
> to this kernel panic happening on real hardware (I can't currently get
> serial out working on my Pi, so I can't test there)
>
> When running qemu 2.10 on Debian, with the command line
>
> qemu-system-arm -machine raspi2 -curses -serial stdio -kernel zImage
> -append "rw earlyprintk loglevel=8 console=ttyAMA0,115200
> dwc_otg.lpm_enable=0 root=ram0" -dtb bcm2710-rpi-3-b.dtb
>
> I get a kernel panic: WARNING: CPU: 0 PID: 1 at
> drivers/tty/serial/serial_core.c:463 uart_get_baud_rate+0xfc/0x160

That's just a warning. The kernel panic is later, because
the init process died for some reason.

Looking at all the warnings and backtraces in the log
that seem to be problems with clock setup, my guess
is that QEMU's model of the clock devices for this board
are missing or wrong, and the kernel then fails to configure
the clocktree, which in turn means the serial port isn't
configured right, and then init dies because it can't
open the thing it's trying to output to.

thanks
-- PMM