Re: [PATCH] serial: Revert serial: core: Fix serial core port id to not use port->line

[Matthew Howell <matthew.howell@sealevel.com>]

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On Tue, 29 Aug 2023, Tony Lindgren wrote:

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> 
> 
> * Matthew Howell <matthew.howell@sealevel.com> [230829 13:42]:
> > On Tue, 29 Aug 2023, Tony Lindgren wrote:
> >
> > > Hi,
> > >
> > > * Matthew Howell <matthew.howell@sealevel.com> [230828 20:41]:
> > > > From: Matthew Howell <matthew.howell@sealevel.com>
> > > > XR17V35X cards seemingly unable to register serial port. Confirmed on
> > > > Sealevel 7202C, 7204EC, and Exar XR17V352 reference board.
> > > > dmesg states: "Couldn't register serial port 0, irq 24, type 2, error -22"
> > > >
> > > > I first identified the problem when I pulled down 6.6-rc1 and I was able
> > > > to trace it to d962de6ae51f9b76ad736220077cda83084090b1. I understand that this
> > > > commit is noted as being reverted in 1ef2c2df1199, but I was only able to
> > > > resolve the issue by reverting d962de6ae51f myself using this patch.
> > >
> > > Thanks for the report. Do you maybe mean 6.5-rc1 instead of 6.6-rc1 above?
> >
> > Apologies, I meant 6.5, no RC. Specifically, I first found this issue on
> > the v6.5 tag (2dde18cd1d8f). I then rolled back until I traced the issue
> > down to the patch in question (d962de6ae51f). Even more specifically,
> > according to my test notes I tested the following commits, with results as
> > indicated:
> >
> > 04c7f60ca477ffbf7b7910320482335050f0d23a -> Not working
> > 3d9e6f556e235ddcdc9f73600fdd46fe1736b090 -> Not working
> > 3c4f8333b582487a2d1e02171f1465531cde53e3 -> Not working
> > a4a79e03bab57729bd8046d22bf3666912e586fb -> Not working
> > 1ef2c2df11997b8135f34adcf2c200d3b4aacbe9 -> Not working
> > d962de6ae51f9b76ad736220077cda83084090b1 -> Not working
> > 282069845af388b08d622ad192b831dcd0549c62 -> Working
> > e6d34ced01bc3aaad616b9446bbaa96cd04617c4 -> Working
> > 748c5ea8b8796ae8ee80b8d3a3d940570b588d59 -> Working
> > 868a9fd9480785952336e5f119e1f75877c423a8 -> Working
> 
> OK
> 
> > What I can say for certain is that of the commits I have tested:
> >
> > 1) Commits before d962de6ae51f work on the hardware I have tested
> > 2) Commits after d962de6ae51f don't work on the hardware I have tested
> > 3) Pulling v6.5 and reverting d962de6ae51f with git revert resolves the
> > issue
> 
> OK. To me it seems uart.port.port_id should be always 0 in exar_pci_probe()
> and get automatically allocated in serial_base_port_add(). Sounds like this
> is not a duplicate port_id issue though but something else as it sounds
> like you're not getting duplicate sysfs entry related errors.
>
> If it is a port_id conflict I'm not sure why commit 3d9e6f556e23 is not
> working for your as it has commit a4a79e03bab5 ("serial: core: Revert
> port_id use"). Care to check that again, or maybe try with v6.5 with just
> the commit below reverted?
> 
> 04c7f60ca477 ("serial: core: Fix serial core port id, including multiport devices")

Just tried that, but no difference. Same error.
 
> Dmesg output might help also to figure out if this happens on the first
> port or the second port.

The full error in dmesg is:
[Aug30 15:48] exar_serial 0000:04:00.0: Couldn't register serial port 0, irq 24, type 2, error -22

This is on a 2-port adapter. I don't see any indication in dmesg that it 
attempted to register the other port.

> Not sure yet where the -22 error here comes from.
>
> Regards,
> 
> Tony
>