Re: RE: [PATCH] printk: nbcon: check uart port is nbcon or not in nbcon_release
From: Sebastian Andrzej Siewior
Date: Wed Jan 17 2024 - 05:25:00 EST
On 2024-01-17 11:09:24 [+0106], John Ogness wrote:
> On 2024-01-17, "Chang, Junxiao" <junxiao.chang@xxxxxxxxx> wrote:
> > There are several serial ports in one Intel ADL hardware, they are
> > enumerated as ttyS0, ttyS1, ttyS4, and so on. Multiple console options
> > might be appended to kernel command line. For example,
> > "console=ttyS0,115200n8 console=ttyS4,115200n8
> > console=ttyS5,115200n8".
> >
> > In this case, several uarts "cons" pointers are same.
>
> So I ask again. Please explain how this is possible.
I have here
| 00:03: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
| 00:04: ttyS1 at I/O 0x2f8 (irq = 3, base_baud = 115200) is a 16550A
and I have
| root 2315 0.0 0.0 5480 1792 ttyS0 Ss+ 11:19 0:00 /sbin/agetty -o -p -- \u --keep-baud 115200,57600,38400,9600 - vt220
| root 2502 0.1 0.0 5480 1792 ttyS1 Ss+ 11:20 0:00 /sbin/agetty -o -p -- \u --keep-baud 115200,57600,38400,9600 - vt220
and I can stop both of them without any trouble.
Can this be reproduced on an ordinary x86 hardware given they have more
than one UART (up to four).
Is any of this ADL hardware upstream?
> John
Sebastian