Re: thud, beaglebone-yocto.conf: SERIAL_CONSOLES setting


Bruce Ashfield <bruce.ashfield@...>
 

On 2018-11-02 4:59 AM, Kevin Hao wrote:
On Fri, Nov 02, 2018 at 09:01:34AM +0100, Heiko Schocher wrote:
Hello Kevin,

Am 01.11.2018 um 03:18 schrieb Kevin Hao:
On Wed, Oct 31, 2018 at 02:23:00PM +0100, Heiko Schocher wrote:
Hello all,

just builded core-image-minimal with current head of thud branch for
the beaglebone-yocto machine, with linux 4.14.x LTS "Linux version 4.14.78",
installed the resulting sd card image and boot it, and get:

INIT: Id "O0" respawning too fast: disabled for
5 minutes

Reason seems to be:

meta-yocto-bsp/conf/machine/beaglebone-yocto.conf

SERIAL_CONSOLES = "115200;ttyO0"

shouldn't this be

SERIAL_CONSOLES = "115200;ttyS0"

With this fix, sd card image boot fine ... may I oversee seomthing
obvious ?
No, it should be 'ttyO0'. It is set by the omap serial driver. You can
refer the following in platform_data/serial-omap.h:
#define OMAP_SERIAL_NAME "ttyO"
Yes, you are right, but I see with linux kernel 4.14.78 from

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.14.y&id=e7405910ca5553eae8744af4e5c03e64ee048cb1

and I see:

[ 0.000000] Linux version 4.14.78 (oe-user@oe-host) (gcc version 8.2.0
(GCC)) #1 Thu Nov 1 10:51:09 UTC 2018
[ 0.000000] CPU: ARMv7 Processor [413fc082] revision 2 (ARMv7), cr=10c5387d
[ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[ 0.000000] OF: fdt: Machine model: TI AM335x BeagleBone Black
[...]
[ 0.362878] Serial: 8250/16550 driver, 6 ports, IRQ sharing disabled
[ 0.365758] 44e09000.serial: ttyS0 at MMIO 0x44e09000 (irq = 30, base_baud = 3000000) is a 8250
[ 1.030465] console [ttyS0] enabled

So definitely a ttyS0 ...
OK, so you don't use the linux-yocto kernel, you must not use the Yocto kernel
meta either. The reason that you got a ttyS0 here is that you use the
8250_omap.c driver. But in Yocto we use the omap-serial.c driver. You can
workaround this issue by enabling SERIAL_8250_OMAP_TTYO_FIXUP.
Thanks Kevin!

I had missed that detail in my reply.

Bruce

Thanks,
Kevin


bye,
Heiko

Thanks,
Kevin


bye,
Heiko
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