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#1 2021-11-24 12:18:07

From: Czech Republic
Registered: 2020-01-28
Posts: 93

[SOLVED] Serial consoles count

Currently there is 32 serial consoles created by kernel.
If I remember, in past only 4 serial consoles were created as described here: … sion_cards

I am limiting them by kernel command line parameter now:


Question: Is it intention to create 32 serial consoles, or is it bug?

Edit: see reply 3

Last edited by GeorgeJP (2021-11-27 18:50:35)


#2 2021-11-27 17:59:48

Registered: 2021-10-04
Posts: 16

Re: [SOLVED] Serial consoles count

I have an arch installation with kernel 5.10.14 and it also has 32 ttyS, so it is definitely not a very recent change.
Going back to even 4.9 (December 2016) the value is still 32: … unk/config and search for *CONFIG_SERIAL_8250_NR_UARTS*.
It seems the parameter has been 32 forever, you just have not noticed. Maybe the documentation you mentioned is simply unclear and describes some process the author used to fix an issue but 4 seems not to be the default value for the package "linux".


#3 2021-11-27 18:18:13

Registered: 2014-03-06
Posts: 14,258

Re: [SOLVED] Serial consoles count … 5516073c12 changed CONFIG_SERIAL_8250_RUNTIME_UARTS from the upstream default of 4 to 32


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