Re: [PATCH 10/11] PCI: Lower bound bridge window alignment

[Bjorn Helgaas <helgaas@kernel.org>]

On Fri, Jun 12, 2026 at 02:50:17PM +0300, Ilpo Järvinen wrote:
> On Wed, 29 Apr 2026, Ilpo Järvinen wrote:
> 
> > pci_resource_alignment() does not consider bridge windows special,
> > yet their alignment is subject to different requirements from BAR
> > alignment.
> > 
> > Add lower bound to bridge window alignment to help callers out to
> > always have large enough alignment.
> > 
> > Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> 
> Hi Bjorn,
> 
> Could you please pull this change and the subsequent one, the commits in 
> pci/resource:
> 
> ae09d28ecbbc ("PCI: Lower bound bridge window alignment")
> cf996b886675 ("PCI: Return valid alignment for assigned resources")

Sure, I dropped these two patches from pci/resource.  The rest are
still heading to v7.2.  Thanks!

> The rest of the changes in this series seem okay and can proceed if you're 
> okay with keeping a partial series.
> 
> The reason for this request is the dev->bus vs dev->subordinate issue 
> sashiko mentioned in its review.
> 
> I've tried to come up with a solution to that but it has become so ugly
> I have not been very happy with it. Maybe there's no other way but the 
> problem boils down with pci_min_window_alignment() having to be capable of 
> dealing two cases, each lacking one of the key pointers (bus or bridge 
> dev):
> 
> 1) root bus without bus->self
> 2) bridge without a subordinate bus struct (if subordinate bus' alloc 
>    failed)
> 
> Only way to solve that I could think of is passing both the bus and the 
> bridge device to pci_min_window_alignment() and the related arch side 
> function pcibios_window_alignment(). The ugliest parts then involve 
> getting a bus pointer compatible with both of those cases, like this:
> 
> 	struct pci_controller *phb = pci_bus_to_host(bus ? bus : bridge->bus);
> 
> But it's too late in the cycle now to try even that, IMO, so better to 
> wait to the next cycle.
> 
> -- 
>  i.