Re: Have my PA8800 back online... (serial port missing on v4.14)

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Tue, 2017-12-12 at 21:11 +0100, Helge Deller wrote:
> On 11.12.2017 09:26, Andy Shevchenko wrote:
> > On Fri, 2017-12-08 at 20:06 +0100, Helge Deller wrote:

> Before your patch this check was inside the function
> serial_pci_guess_board()
> and if (ent->driver_data != pbn_default) the pci serial port got
> registered 
> and initialized *even* if it's *not* of class SERIAL or MODEM.

Ah, okay, it explains indeed.
Though PCI devices with wrong class should have their own quirks for my
p.o.v.

> > (Of course, I agree this is regression and needs to be fixed ASAP)
> 
> I don't know if it's easy to fix without reverting your patch.

As I explained earlier it's about pci_enable_device() called twice for
the same device which basically calls pcibios_enable_irq() twice which
might be a problem on some platforms. (At least I have such use case).
Perhaps it's possible to workaround the issue on those platforms, though
I didn't come up with the better solution that time.

> Thanks for the offer to accept this patch, but maybe we are able
> to come up with another patch which simply hides those unsupported
> devices (serial port and ATI graphics card device on the Diva card).
> I posted a proposed patch here:
> http://www.spinics.net/lists/linux-parisc/msg08187.html

Reading briefly that one I guess it's even better (now I realized you
even do not have connectors of those devices outside).

> But I wonder if we are the only platform which notice this different
> behavior now. I assume others will notice it soon too.

Why so? Most of the 8250 PCI devices are enumerated by class. Others
have no such misclassification.

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy