On Mon, Oct 29, 2018 at 06:46 PM, Chen, Jason CJ wrote:

After change vuart irq from 4 to 6, the SOS kernel config need enable CONFIG_SERIAL_8250_DETECT_IRQ,

Hi Jason,

Thanks for your reply. Of course I made sure this option was set in my .config file.
> grep CONFIG_SERIAL_8250_DETECT_IRQ kernel_config_uefi_sos
> CONFIG_SERIAL_8250_DETECT_IRQ=y

Moreover this option is set by default in the kernel_config_uefi_sos file in the acrn_kernel repository and I didn't change it.
However linux keeps choosing IRQ 4 for uart0, ...
I just recompiled everything (of course with acrn COM1_IRQ set to 6 and CONFIG_SERIAL_8250_DETECT_IRQ=y) and I still get in the boot trace:

> ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A

Last Friday, I even changed the default configuration in arch/x86/include/asm/serial.h

{ .uart = 0,    BASE_BAUD,    0x3F8,    6,    STD_COMX_FLAGS    }, /* ttyS0 */

but still got in my traces

> ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A

My opinion is that something makes linux believe the uart is really on IRQ 4...

Thanks,
Joe