From 9629f71722bb994f4b95088bc37a14f9aeaa5f90 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 19 Dec 2025 19:40:24 +0200 Subject: [PATCH] PCI: Log reset and restore of resources MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20251219174036.16738-12-ilpo.jarvinen@linux.intel.com --- drivers/pci/setup-bus.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 403139d8c86a..a5b6c555a45b 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -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; -- 2.47.3