From 0f8b5d90d179b9639be1dbeff59d6d971e6b0527 Mon Sep 17 00:00:00 2001 From: Alexander Gruhlke Date: Sun, 11 Oct 2026 21:01:44 +0200 Subject: [PATCH 1/2] PCI: Ignore Immediate Readiness on Samsung 990 PRO and 990 EVO Plus NVMe The Samsung 990 PRO [144d:a80c] advertises Immediate Readiness, so pcie_flr() doesn't wait after FLR, but the drive returns ~0 for up to 7 ms. Since commit 10baa9b4df40 ("PCI: Drop unnecessary retries when restoring BARs"), the config restore after FLR is lost, which breaks VFIO passthrough of the drive. Firmware 8B2QJXD7 responds right after FLR, but older firmware such as 1B2QJXD7 doesn't, and the firmware version isn't visible here. [bhelgaas: The Samsung 990 EVO Plus [144d:a80d] with 2B2QKXG7 firmware seems to have the same problem.] Ignore Immediate Readiness on these devices, so pcie_flr() waits. Fixes: 10baa9b4df40 ("PCI: Drop unnecessary retries when restoring BARs") Link: https://bbs.archlinux.org/viewtopic.php?id=314833 Link: https://bbs.archlinux.org/viewtopic.php?pid=2312085#p2312085 Suggested-by: Lukas Wunner Assisted-by: Claude:claude-opus-5-5 Signed-off-by: Alexander Gruhlke [bhelgaas: squashed in Samsung 990 EVO Plus from https://lore.kernel.org/all/20261016102042.641801-1-gruhlke@mailbox.org] Signed-off-by: Bjorn Helgaas Reviewed-by: Lukas Wunner Link: https://patch.msgid.link/20261011190145.23621-2-gruhlke@mailbox.org Link: https://patch.msgid.link/20261016102042.641801-1-gruhlke@mailbox.org --- drivers/pci/quirks.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index de9bbccda21f..0d8c47a46ce9 100644 --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -5623,6 +5623,18 @@ static void quirk_no_flr_snet(struct pci_dev *dev) } DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_SOLIDRUN, 0x1000, quirk_no_flr_snet); +/* Some Samsung SSDs advertise Immediate Readiness but aren't ready after FLR */ +static void quirk_no_imm_ready(struct pci_dev *dev) +{ + if (!dev->imm_ready) + return; + + pci_info(dev, "Ignoring incorrectly advertised Immediate Readiness support\n"); + dev->imm_ready = 0; +} +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SAMSUNG, 0xa80c, quirk_no_imm_ready); +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_SAMSUNG, 0xa80d, quirk_no_imm_ready); + static void quirk_no_ext_tags(struct pci_dev *pdev) { struct pci_host_bridge *bridge = pci_find_host_bridge(pdev->bus); From e8df1d194c39b7a5159d570798941851f70a8668 Mon Sep 17 00:00:00 2001 From: Alexander Gruhlke Date: Sun, 11 Oct 2026 21:01:45 +0200 Subject: [PATCH 2/2] PCI: Don't treat ~0 as ready in pci_dev_wait() with RRS SV 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 --- 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 b2879a6be5f8..d80e52421bf0 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1246,9 +1246,11 @@ 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 @@ -1268,8 +1270,13 @@ 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))