** Description changed:
+ [Impact]
+
Raspberry Pi OS is configured with CONFIG_SERIAL_8250_NR_UARTS=5 which
is different to the Ubuntu 24.04 LTS for Raspberry PI
(CONFIG_SERIAL_8250_NR_UARTS=1).
The Broadcom BCM7271 UART uses that one 8250 Serial UART meaning none
are left for user configuration and use. I came across this whilst using
an RS485 PCIE board that has 4 UART ports. None were about to
initialise, and the driver gave the error `Couldn't register serial ...
error -28`. To resolve this I reconfigured and compiled the kernel with
`CONFIG_SERIAL_8250_NR_UARTS=32`
Raspberry Pi OS decided on 5, but I would be interested to know why it
shouldn't be higher. We looked at PCIE boards that can have up to 8 UART
ports which would require at least CONFIG_SERIAL_8250_NR_UARTS=9
I am using `Ubuntu 24.04.1 LTS` with `linux-raspi 6.8.0-1017.19`
Before reporting here I also made a post here
https://discourse.ubuntu.com/t/limited-8250-serial-ports-on-
ubuntu-24-04-raspberry-pi/54064
I not familiar with the process of resolving bugs but I would be
interested in contributing!
Thank you!
+
+ [Test Case]
+
+ With relevant HW, check that the UARTS are available.
+
+ [Where Problems Could Occur]
+
+ Enables more UARTs, so anything UART related could break.
** Also affects: linux-raspi (Ubuntu Noble)
Importance: Undecided
Status: New
** Also affects: linux-raspi (Ubuntu Oracular)
Importance: Undecided
Status: New
** Summary changed:
- kernal compiled with different CONFIG_SERIAL_8250_NR_UARTS to Raspberry Pi OS
+ Kernel compiled with different CONFIG_SERIAL_8250_NR_UARTS to Raspberry Pi OS
** Description changed:
[Impact]
Raspberry Pi OS is configured with CONFIG_SERIAL_8250_NR_UARTS=5 which
is different to the Ubuntu 24.04 LTS for Raspberry PI
(CONFIG_SERIAL_8250_NR_UARTS=1).
The Broadcom BCM7271 UART uses that one 8250 Serial UART meaning none
are left for user configuration and use. I came across this whilst using
an RS485 PCIE board that has 4 UART ports. None were about to
initialise, and the driver gave the error `Couldn't register serial ...
error -28`. To resolve this I reconfigured and compiled the kernel with
`CONFIG_SERIAL_8250_NR_UARTS=32`
Raspberry Pi OS decided on 5, but I would be interested to know why it
shouldn't be higher. We looked at PCIE boards that can have up to 8 UART
ports which would require at least CONFIG_SERIAL_8250_NR_UARTS=9
I am using `Ubuntu 24.04.1 LTS` with `linux-raspi 6.8.0-1017.19`
Before reporting here I also made a post here
https://discourse.ubuntu.com/t/limited-8250-serial-ports-on-
ubuntu-24-04-raspberry-pi/54064
I not familiar with the process of resolving bugs but I would be
interested in contributing!
Thank you!
[Test Case]
- With relevant HW, check that the UARTS are available.
+ With relevant HW, check that the UARTs are available.
[Where Problems Could Occur]
Enables more UARTs, so anything UART related could break.
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2096796
Title:
Kernel compiled with different CONFIG_SERIAL_8250_NR_UARTS to
Raspberry Pi OS
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux-raspi/+bug/2096796/+subscriptions
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
