Re: [PATCH 24/25] PCI: Perform reset_resource() and build fail list in sync

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Tue, 3 Jun 2025, Ilpo Järvinen wrote:

> On Tue, 3 Jun 2025, Tudor Ambarus wrote:
> > On 6/3/25 11:48 AM, Tudor Ambarus wrote:
> > > On 6/3/25 11:36 AM, Tudor Ambarus wrote:
> > >> On 6/3/25 9:13 AM, Ilpo Järvinen wrote:
> > >>> So please test if this patch solves your problem:
> > >>
> > >> It fails in a different way, the bridge window resource never gets
> > >> assigned with the proposed patch.
> > >>
> > >> With the patch applied: https://termbin.com/h3w0
> > > 
> > > above is no revert and with the proposed fix. It also contains the
> > > prints https://termbin.com/g4zn
> > > 
> > > It seems the prints in pbus_size_mem are not longer hit, likely because
> > > of the new condition added: ``!pdev_resources_assignable(dev) ||``,
> > > pci_dev_for_each_resource() finishes without doing anything.
> > > 
> > >> With the blamed commit reverted: https://termbin.com/3rh6
> > > 
> > 
> > I think I found the inconsistency.
> > 
> > __pci_bus_assign_resources()
> > 	pbus_assign_resources_sorted()
> > 		pdev_sort_resources(dev, &head);
> > 
> > But pdev_sort_resources() is called with a newly LIST_HEAD(head), not
> > with realloc_head, thus the resources never get sorted.
> 
> pdev_sort_resources() is not supposed to add resources into realloc_head 
> but just collects all the relevant resources in the descending order by
> size.

Small correction, they're ordered by alignment, not by size. For other 
than iov resources and bridge window, alignment order effectively the same 
as size order.

> There are two main lists here. The head list contains all relevant 
> resources we're going to process and realloc_head keeps track which of 
> them are optional (or optional in part, that is, some resources have the 
> base size and the optional size).
> 
> __assign_resources_sorted() will apply the optional sizes from 
> realloc_head and re-sorts the head list while changing the sizes.
> If not all resources can be assigned, rollback happens and base sizes are 
> assigned first, and then reassign_resources_sorted() handles the 
> realloc_head ones afterwards for as many resources as possible.
> 
> > pdev_sort_resources() exits early at
> > 	``if (!pdev_resources_assignable(dev))``
> 
> Yes it does, for 0001:01:00.0.
> 
> 

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 i.