The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 92597f97a40bf661bebceb92e26ff87c76d562d4 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" rafael.j.wysocki@intel.com Date: Thu, 31 Mar 2022 19:38:51 +0200 Subject: [PATCH] PCI/PM: Avoid putting Elo i2 PCIe Ports in D3cold
If a Root Port on Elo i2 is put into D3cold and then back into D0, the downstream device becomes permanently inaccessible, so add a bridge D3 DMI quirk for that system.
This was exposed by 14858dcc3b35 ("PCI: Use pci_update_current_state() in pci_enable_device_flags()"), but before that commit the Root Port in question had never been put into D3cold for real due to a mismatch between its power state retrieved from the PCI_PM_CTRL register (which was accessible even though the platform firmware indicated that the port was in D3cold) and the state of an ACPI power resource involved in its power management.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=215715 Link: https://lore.kernel.org/r/11980172.O9o76ZdvQC@kreacher Reported-by: Stefan Gottwald gottwald@igel.com Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Cc: stable@vger.kernel.org # v5.15+
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 9ecce435fb3f..d25122fbe98a 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -2920,6 +2920,16 @@ static const struct dmi_system_id bridge_d3_blacklist[] = { DMI_MATCH(DMI_BOARD_VENDOR, "Gigabyte Technology Co., Ltd."), DMI_MATCH(DMI_BOARD_NAME, "X299 DESIGNARE EX-CF"), }, + /* + * Downstream device is not accessible after putting a root port + * into D3cold and back into D0 on Elo i2. + */ + .ident = "Elo i2", + .matches = { + DMI_MATCH(DMI_SYS_VENDOR, "Elo Touch Solutions"), + DMI_MATCH(DMI_PRODUCT_NAME, "Elo i2"), + DMI_MATCH(DMI_PRODUCT_VERSION, "RevB"), + }, }, #endif { }