Re: [PATCH v3 00/10] ARM: tegra: Add PCIe device tree support

[Stephen Warren <swarren@wwwdotorg.org>]

On 09/07/2012 06:04 PM, Russell King - ARM Linux wrote:
> On Fri, Sep 07, 2012 at 05:34:35PM -0600, Stephen Warren wrote:
>> I guess it's a pretty basic premise of the current PCI code that all the
>> PCI scanning happens well before any device drivers are registered,
>> which in turn means that device_add() doesn't trigger the device's
>> probe() until much later, after all the fixups and resource assignments
>> are done?
> 
> Are you saying that the PCI layer is again screwed up after all my
> hard work several years ago to ensure that PCI devices are properly
> setup _before_ they're made available to the PCI drivers then?  That
> was around the time I was looking at Cardbus stuff, ensuring that that
> worked with the same guarantees.
> 
> Not amused.
> 
> What is wrong with the "probe devices, apply fixups, setup resources,
> apply more fixups, publish" process that it's had to be yet again
> broken?

I must admit, I'm having a hard time finding when the code worked like
that; ARM's bios32.c:pcibios_init_hw() seems to have always called
pci_scan_root_bus(), or ops function hw->scan(), which at least in the 1
PCIe controller driver I looked at, in turn always called either
pci_scan_root_bus() or another similar function that I believe always
called pci_bus_add_devices(), which is before pci_common_init() could
assign the resources. Maybe I'm just looking at the wrong PCIe
controller driver, or not looking back far enough in git history (or
pre-git)? If you could point out when it was working as you describe
(which sounds reasonable), I'd be interested in tracing the history from
there to see when/why it changed.