Re: [PATCH v2] platform/x86: p2sb: Defer P2SB device scan when P2SB device has func 0

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 3/4/24 3:17 PM, Andy Shevchenko wrote:
> On Mon, Mar 04, 2024 at 04:09:49PM +0200, Andy Shevchenko wrote:
>> On Mon, Mar 04, 2024 at 02:59:57PM +0100, Hans de Goede wrote:
>>> On 3/4/24 1:13 PM, Shinichiro Kawasaki wrote:
>>>> On Mar 04, 2024 / 12:04, Hans de Goede wrote:
> 
> ...
> 
>>>> Thanks for sharing the insights.
>>>
>>> Looking closer at the actual unhiding I don't think accessing func 0
>>> is the problem. The unhiding is always done on function 0 even when
>>> retreiving the bar for function 2 (the SPI function).
>>>
>>> So taking that into account, as mentioned in the bugzilla, I think
>>> the problem is probing the other functions (1, 3-7) by calling
>>> pci_scan_single_device() on them.
>>
>> So, why we can't simply call pci_dev_present() on the function in a loop?
> 
> pci_device_is_present()

That takes a pci_dev as argument which we only have after calling
pci_scan_single_device() and the calling of pci_scan_single_device()
on some of the other functions is what is suspected of maybe causing
the issue.

Also it is likely that if pci_scan_single_device() is actually
a problem that then what is a problem is running it on an actual
present device. Devices which are not there also should not get confused
by trying to probe them ...

Regards,

Hans