Commit 9629f717 authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by Bjorn Helgaas
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PCI: Log reset and restore of resources 



PCI resource fitting and assignment is complicated to track because it
performs many actions without any logging. One of these is resource reset
(zeroing the resource) and the restore during the multi-pass resource
fitting algorithm.

Resource reset does not play well with the other PCI code if the code later
wants to reattempt assignment of that resource. Knowing that a resource was
left in the reset state without a pairing restore is useful for
understanding issues that show up as resource assignment failures.

Add pci_dbg() to both reset and restore to be better able to track what's
going on within the resource fitting algorithm.

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Link: https://patch.msgid.link/20251219174036.16738-12-ilpo.jarvinen@linux.intel.com
parent 5fa2f9fb

drivers/pci/setup-bus.c

+9 −1
Original line number Diff line number Diff line
@@ -136,6 +136,9 @@ static resource_size_t get_res_add_align(struct list_head *head, 
static void restore_dev_resource(struct pci_dev_resource *dev_res)

{

	struct resource *res = dev_res->res;

	struct pci_dev *dev = dev_res->dev;

	int idx = pci_resource_num(dev, res);

	const char *res_name = pci_resource_name(dev, idx);



	if (WARN_ON_ONCE(res->parent))

		return;
@@ -143,6 +146,8 @@ static void restore_dev_resource(struct pci_dev_resource *dev_res) 
	res->start = dev_res->start;

	res->end = dev_res->end;

	res->flags = dev_res->flags;



	pci_dbg(dev, "%s %pR: resource restored\n", res_name, res);

}



/*
@@ -384,15 +389,18 @@ bool pci_resource_is_optional(const struct pci_dev *dev, int resno) 
	return false;

}



static inline void reset_resource(struct pci_dev *dev, struct resource *res)

static void reset_resource(struct pci_dev *dev, struct resource *res)

{

	int idx = pci_resource_num(dev, res);

	const char *res_name = pci_resource_name(dev, idx);



	if (pci_resource_is_bridge_win(idx)) {

		res->flags |= IORESOURCE_UNSET;

		return;

	}



	pci_dbg(dev, "%s %pR: resetting resource\n", res_name, res);



	res->start = 0;

	res->end = 0;

	res->flags = 0;