On Mon, Sep 05, 2022 at 02:56:22PM +0800, Kai-Heng Feng wrote: > AMD USB4 can not detect external PCIe devices like external NVMe when > it's hotplugged, because card/link are not up: > > pcieport 0000:00:04.1: pciehp: pciehp_check_link_active: lnk_status = 1101 That sounds like a hardware bug, how does this work in other operating systems for this hardware? > Use `lspci` to resume pciehp bridges can find external devices. That's not good :( > A long delay before checking card/link presence doesn't help, either. > The only way to make the hotplug work is to enable pciehp interrupt and > check card presence after the TB switch is added. > > Since the topology of USB4 and its PCIe bridges are siblings, hardcode > the bridge ID so TBT driver can wake them up to check presence. As I mention below, this is not an acceptable solution. AMD developers, any ideas on how to get this fixed in the TB controller firware instead? > > Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=216448 > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> > --- > drivers/thunderbolt/nhi.c | 29 +++++++++++++++++++++++++++++ > drivers/thunderbolt/switch.c | 6 ++++++ > drivers/thunderbolt/tb.c | 1 + > drivers/thunderbolt/tb.h | 5 +++++ > include/linux/thunderbolt.h | 1 + > 5 files changed, 42 insertions(+) > > diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c > index cb8c9c4ae93a2..75f5ce5e22978 100644 > --- a/drivers/thunderbolt/nhi.c > +++ b/drivers/thunderbolt/nhi.c > @@ -1225,6 +1225,8 @@ static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id) > { > struct tb_nhi *nhi; > struct tb *tb; > + struct pci_dev *p = NULL; > + struct tb_pci_bridge *pci_bridge, *n; > int res; > > if (!nhi_imr_valid(pdev)) { > @@ -1306,6 +1308,19 @@ static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id) > nhi_shutdown(nhi); > return res; > } > + > + if (pdev->vendor == PCI_VENDOR_ID_AMD) { > + while ((p = pci_get_device(PCI_VENDOR_ID_AMD, 0x14cd, p))) { > + pci_bridge = kmalloc(sizeof(struct tb_pci_bridge), GFP_KERNEL); > + if (!pci_bridge) > + goto cleanup; > + > + pci_bridge->bridge = p; > + INIT_LIST_HEAD(&pci_bridge->list); > + list_add(&pci_bridge->list, &tb->bridge_list); > + } > + } You can't walk the device tree and create a "shadow" list of devices like this and expect any lifetime rules to work properly with them at all. Please do not do this. greg k-h
