On 8/5/23 08:50, Guenter Roeck wrote:
On 8/5/23 04:48, Tony Lindgren wrote:
* Guenter Roeck <linux@xxxxxxxxxxxx> [230805 10:50]:
On 8/4/23 21:49, Tony Lindgren wrote:
* Guenter Roeck <linux@xxxxxxxxxxxx> [230804 21:42]:
kobject: kobject_add_internal failed for serial8250.0:0.0 with -EEXIST, don't try to register things with the same name in the same directory.
serial8250 serial8250.0: unable to register port at index 1 (IO2f8 MEM0 IRQ3): -17
sysfs: cannot create duplicate filename '/devices/platform/serial8250.0/serial8250.0:0/serial8250.0:0.0'
The issue above should be fixed with commit:
bbb4abb1bcfb ("serial: 8250: Reinit port_id when adding back serial8250_isa_devs")
No. I tested the tip of tty-linus (v6.5-rc4-9-gdfe2aeb226fd) which includes
above commit, but still see the problem. sparc images also still stall after
the "cannot create duplicate filename" message.
I bisected the sparc problem - it also bisects to commit d962de6ae51f.
The problem affects all mips boot tests, all sparc boot tests, as well as
arm sx1, ppc bamboo and sam460ex emulations. As far as I can see, those
call serial8250_register_8250_port() without calling serial8250_setup_port()
and thus don't set port_id. I am only testing a few of those, so I strongly
suspect that all similar callers of serial8250_register_8250_port() are
affected (i.e., almost all of them) if they register more than one serial port.
OK thanks for explaining. So we need to initialize port->port_id for the
multi-port instances to avoid being stuck with the port->line index. I'll
take a look.
I wonder if we should just revert d962de6ae51f for now. It needs to be
tested to see if something else also needs reverting though.
It is actually more complicated like that. Adding some debug into, I get the following
from a mips boot. Turns out that serial8250_setup_port() is actually called.
...
####### serial8250_setup_port: index 0
####### serial8250_setup_port: index 0 returning 819a5ab8
####### serial8250_setup_port: index 1
####### serial8250_setup_port: index 1 returning 819a5d20
####### serial8250_setup_port: index 2
####### serial8250_setup_port: index 2 returning 819a5f88
####### serial8250_setup_port: index 3
####### serial8250_setup_port: index 3 returning 819a61f0
...
#### serial8250_register_8250_port: uart=819a5ab8
#### serial8250_register_8250_port: uart=819a5ab8 port_id=0 line=0
...
#### serial8250_register_8250_port: uart=819a5d20
#### serial8250_register_8250_port: uart=819a5d20 port_id=1 line=1
sysfs: cannot create duplicate filename '/devices/platform/serial8250.0/serial8250.0:0/serial8250.0:0.0'
So line and port_id are both set, but the created sysfs attribute
is still duplicate. I'll do some more debugging.
Ok, it is actually quite simple. In serial8250_register_8250_port(),
uart->port.port_id has the correct and expected value. However, that is
overwritten with
uart->port.port_id = up->port.port_id;
where 'up' is the port pointer passed by the caller of serial8250_register_8250_port().
And 'port_id' is always 0 in _that_ port pointer (while 'line' is set correctly).
Guenter
