On 1/29/2018 4:43 PM, Dave Airlie wrote:

quoted

 12/19/2017 12:37 AM, Sinan Kaya wrote:

quoted

pci_get_bus_and_slot() is restrictive such that it assumes domain=0 as
where a PCI device is present. This restricts the device drivers to be
reused for other domain numbers.

So not a major problem, but it would be pretty much impossible for either
of these agp drivers to be used in any other domain ever.

What does this buy us, maybe just rename pci_get_bus_and_slot to
pci_get_domain0_bus_and_slot as a helper, or just pass the pdev in
and have it do the right thing always.

There is nothing wrong with doing all three. Since nobody replied until
patch v4, I did the heavy-lifting and converted code to use pci_domain_nr()
as much as I can rather than hard-coding a 0 while calling
pci_get_domain_bus_and_slot().

From PCI coding perspective, pci_domain_nr() call is the right thing. It is

guaranteed to work no matter what your domain number is. 

People look at other code for examples on how to write a PCI driver
in general. You want to minimize the exceptions as much as possible.

Some discussion here about the benefits:

https://lkml.org/lkml/2017/12/19/349


-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.