Re: [master][PATCH] am62lxx-evm: Override serial console to ttyS0 only

On 4/22/26 11:39 AM, Randolph Sapp wrote:
> On Wed Apr 22, 2026 at 1:22 AM CDT, Yogesh Hegde wrote:
>> The am62lxx-evm board only has ttyS0 available. The k3 default
>> SERIAL_CONSOLES inherited includes ttyS2, which causes
>> systemd to wait indefinitely for a console that never appears,
>> significantly increasing boot time and degrading user experience.
>>
>> Override SERIAL_CONSOLES to specify only ttyS0, allowing the boot
>> process to proceed normally without waiting for unavailable consoles.
>>
>> Signed-off-by: Yogesh Hegde <[email protected]>
>> ---
>>
>> Boot time is increased from 33s to 2m18s.
>> Boot time is measured from power on to TI LVGL demo
>> running on HDMI Display.
>>
>> Logs:
>>
>> root@am62lxx-evm:~# systemd-analyze critical-chain ti-lvgl-demo.service
>> The time when unit became active or started is printed after the "@" character.
>> The time the unit took to start is printed after the "+" character.
>> ti-lvgl-demo.service @1min 32.588s
>> `-multi-user.target @1min 32.577s
>>    `-getty.target @1min 32.575s
>>      `[email protected] @13.002s
>>        `-systemd-user-sessions.service @10.847s +660ms
>>          `-network.target @10.582s
>>            `-systemd-networkd.service @8.748s +1.799s
>>              `-network-pre.target @8.735s
>>                `-iptables.service @7.477s +920ms
>>                  `-basic.target @7.363s
>>                    `-dbus-broker.service @6.661s +466ms
>>                      `-dbus.socket @6.310s +434us
>>                        `-sysinit.target @6.263s
>>                          `-systemd-vconsole-setup.service @18.198s +391ms
>>                            `-systemd-journald.socket @2.781s +335us
>>                              `-system.slice @1.282s
>>                                `--.slice @1.282s
>>
>>  From the time analysis log, `getty.target` takes 1min 32 secs to bootup due to
>> [email protected] failed. This service fails because there is no
>> hardware associated with ttyS2.
>>
>> ---
>>   meta-ti-bsp/conf/machine/am62lxx-evm.conf | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/meta-ti-bsp/conf/machine/am62lxx-evm.conf b/meta-ti-bsp/conf/machine/am62lxx-evm.conf
>> index 677d6955..edfb4057 100644
>> --- a/meta-ti-bsp/conf/machine/am62lxx-evm.conf
>> +++ b/meta-ti-bsp/conf/machine/am62lxx-evm.conf
>> @@ -4,6 +4,8 @@
>>   
>>   require conf/machine/include/am62lxx.inc
>>   
>> +SERIAL_CONSOLES = "115200;ttyS0"
>> +
>>   IMAGE_FSTYPES += "ubifs ubi"
>>   
>>   MKUBIFS_ARGS ?= "-F -m 4096 -e 258048 -c 12000"
> 
> Systemd's getty generator might still try to grab ttyS0 in other scenarios, but
> this at least fixes the default behavior of trying to wait for the kernel serial
> console on this board.
> 
> Out of curiosity, why did this change for this board? As I recall Andrew and
> Nishanth had a debate about this a few years back and the result was to
> standardize to ttyS2 for all k3.
> 

AM62L isn't "K3" in a way, it doesn't have the R5 cores taking up a UART.
While we probably could have aliased the first MAIN domain UART to ttyS2
anyway, this feels like a good time to get back to the more standard
"default UART == ttyS0" that everyone else goes by.

> Reviewed-by: Randolph Sapp <[email protected]>