7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexander Gruhlke [ Upstream commit e8df1d194c39b7a5159d570798941851f70a8668 ] With RRS Software Visibility, pci_dev_wait() considers a device ready as soon as reading the Vendor ID doesn't return the RRS value. Devices aren't required to respond with RRS while they aren't ready, so the read may return ~0 and pci_dev_wait() stops waiting too early. This was seen with Intel [8086:0a54] and Samsung [144d:a80c] NVMe SSDs. Also wait while the Vendor ID reads ~0. A VF's Vendor ID always reads ~0, so check its Command register instead, as is done without RRS SV. Fixes: d591f6804e7e ("PCI: Wait for device readiness with Configuration RRS") Link: https://lore.kernel.org/r/20250611101442.387378-1-hui.wang@canonical.com Suggested-by: Lukas Wunner Assisted-by: Claude:claude-opus-5-5 Signed-off-by: Alexander Gruhlke Signed-off-by: Bjorn Helgaas Reviewed-by: Lukas Wunner Link: https://patch.msgid.link/20261011190145.23621-3-gruhlke@mailbox.org Signed-off-by: Sasha Levin --- drivers/pci/pci.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 80d2338b2a0a8..c8be53376ff3b 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1213,9 +1213,11 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout) * initialize. * * If the device is below a Root Port with Configuration RRS - * Software Visibility enabled, reading the Vendor ID returns a + * Software Visibility enabled, reading the Vendor ID may return a * special data value if the device responded with RRS. Read the - * Vendor ID until we get non-RRS status. + * Vendor ID until we get non-RRS status and something other than + * ~0. The Vendor ID of VFs reads ~0, so check their Command + * register instead. * * If there's no Root Port or Configuration RRS Software Visibility * is not enabled, the device may still respond with RRS, but @@ -1235,8 +1237,13 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout) if (root && root->config_rrs_sv) { pci_read_config_dword(dev, PCI_VENDOR_ID, &id); - if (!pci_bus_rrs_vendor_id(id)) - break; + if (!pci_bus_rrs_vendor_id(id)) { + if (PCI_POSSIBLE_ERROR(id) && dev->is_virtfn) + pci_read_config_dword(dev, PCI_COMMAND, + &id); + if (!PCI_POSSIBLE_ERROR(id)) + break; + } } else { pci_read_config_dword(dev, PCI_COMMAND, &id); if (!PCI_POSSIBLE_ERROR(id)) -- 2.53.0