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Manual PCI rescan succeeds,\nproving devices are present and functional on the bus.\n\nSolution:\n\nSchedule a delayed pci_rescan_bus() (300ms) after tunnel activation.\nSince pci_rescan_bus() is idempotent and won't re-add already-enumerated\ndevices, we unconditionally rescan rather than comparing device counts.\nThis is non-blocking and avoids overhead on systems where pciehp works\ncorrectly, as the rescan is a no-op when devices are already present.\n\nSigned-off-by: Chia-Lin Kao (AceLan) \n(cherry picked from commit https://lore.kernel.org/lkml/20260121060857.237777-1-acelan.kao@canonical.com/T/#u)\nSigned-off-by: Chia-Lin Kao (AceLan) \n---\n drivers/thunderbolt/tb.c | 35 +++++++++++++++++++++++++++++++++++\n 1 file changed, 35 insertions(+)","diff":"diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c\nindex c69c323e6952a..4967ceab83109 100644\n--- a/drivers/thunderbolt/tb.c\n+++ b/drivers/thunderbolt/tb.c\n@@ -11,6 +11,7 @@\n #include \n #include \n #include \n+#include \n \n #include \"tb.h\"\n #include \"tb_regs.h\"\n@@ -18,6 +19,7 @@\n \n #define TB_TIMEOUT\t\t100\t/* ms */\n #define TB_RELEASE_BW_TIMEOUT\t10000\t/* ms */\n+#define TB_PCIEHP_ENUMERATION_DELAY 300\t/* ms */\n \n /*\n * How many time bandwidth allocation request from graphics driver is\n@@ -83,6 +85,12 @@ struct tb_hotplug_event {\n \tint retry;\n };\n \n+/* Delayed work to rescan PCIe bus after tunnel activation */\n+struct tb_pci_rescan_work {\n+\tstruct delayed_work work;\n+\tstruct pci_bus *bus;\n+};\n+\n static void tb_scan_port(struct tb_port *port);\n static void tb_handle_hotplug(struct work_struct *work);\n static void tb_dp_resource_unavailable(struct tb *tb, struct tb_port *port,\n@@ -90,6 +98,17 @@ static void tb_dp_resource_unavailable(struct tb *tb, struct tb_port *port,\n static void tb_queue_dp_bandwidth_request(struct tb *tb, u64 route, u8 port,\n \t\t\t\t\t int retry, unsigned long delay);\n \n+static void tb_pci_rescan_work_fn(struct work_struct *work)\n+{\n+\tstruct tb_pci_rescan_work *rescan_work =\n+\t\tcontainer_of(work, typeof(*rescan_work), work.work);\n+\n+\tpci_lock_rescan_remove();\n+\tpci_rescan_bus(rescan_work->bus);\n+\tpci_unlock_rescan_remove();\n+\tkfree(rescan_work);\n+}\n+\n static void tb_queue_hotplug(struct tb *tb, u64 route, u8 port, bool unplug)\n {\n \tstruct tb_hotplug_event *ev;\n@@ -2313,6 +2332,22 @@ static int tb_tunnel_pci(struct tb *tb, struct tb_switch *sw)\n \t\ttb_sw_warn(sw, \"failed to connect xHCI\\n\");\n \n \tlist_add_tail(&tunnel->list, &tcm->tunnel_list);\n+\n+\t/* Schedule a delayed PCIe bus rescan in case pciehp misses devices */\n+\tif (tb->nhi && tb->nhi->pdev && tb->nhi->pdev->bus) {\n+\t\tstruct pci_bus *bus = tb->nhi->pdev->bus;\n+\t\tstruct tb_pci_rescan_work *rescan_work;\n+\n+\t\trescan_work = kmalloc(sizeof(*rescan_work), GFP_KERNEL);\n+\t\tif (!rescan_work)\n+\t\t\treturn 0;\n+\n+\t\trescan_work->bus = bus->parent ? bus->parent : bus;\n+\t\tINIT_DELAYED_WORK(&rescan_work->work, tb_pci_rescan_work_fn);\n+\t\tqueue_delayed_work(tb->wq, &rescan_work->work,\n+\t\t\t\t msecs_to_jiffies(TB_PCIEHP_ENUMERATION_DELAY));\n+\t}\n+\n \treturn 0;\n }\n \n","prefixes":["SRU","R","1/1"]}