[ Upstream commit f3380cac0c0b3a6f49ab161e2a057c363962f48d ]
If protocol tunnels are already up when the driver is loaded, for
instance if the boot firmware implements connection manager of its own,
runtime PM reference count of the consumer devices behind the tunnel
might have been increased already before the device link is created but
the supplier device runtime PM reference count is not. This leads to a
situation where the supplier (the Thunderbolt driver) can runtime
suspend even if it should not because the corresponding protocol tunnel
needs to be up causing the devices to be removed from the corresponding
native bus.
Prevent this from happening by making both sides of the link runtime PM
active briefly. The pm_runtime_put() for the consumer (PCIe
root/downstream port, xHCI) then allows it to runtime suspend again but
keeps the supplier runtime resumed the whole time it is runtime active.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 4d395c5e74398f664405819330e5a298da37f655 upstream.
When we walk up the device hierarchy in tb_acpi_add_link() make sure we
break the loop if the device has no parent. Otherwise we may crash the
kernel by dereferencing a NULL pointer.
Fixes: b2be2b05cf ("thunderbolt: Create device links from ACPI description")
Cc: stable@vger.kernel.org
Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Acked-by: Yehezkel Bernat <YehezkelShB@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The new way to describe relationship between tunneled ports and USB4 NHI
(Native Host Interface) is with ACPI _DSD looking like below for a PCIe
downstream port:
Scope (\_SB.PCI0)
{
Device (NHI0) { } // Thunderbolt NHI
Device (DSB0) // Hotplug downstream port
{
Name (_DSD, Package () {
ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
Package () {
Package () {"usb4-host-interface", \_SB.PCI0.NHI0},
...
}
})
}
}
This is "documented" in these [1] USB-IF slides and being used on
systems that ship with Windows.
The _DSD can be added to tunneled USB3 and PCIe ports, and is needed to
make sure the USB4 NHI is resumed before any of the tunneled ports so
the protocol tunnels get established properly before the actual port
itself is resumed. Othwerwise the USB/PCI core find the link may not be
established and starts tearing down the device stack.
This parses the ACPI description each time NHI is probed and tries to
find devices that has the property and it references the NHI in
question. For each matching device a device link from that device to the
NHI is created.
Since USB3 ports themselves do not get runtime suspended with the parent
device (hub) we do not add the link from the USB3 port to USB4 NHI but
instead we add the link from the xHCI device. This makes the device link
usable for runtime PM as well.
[1] https://www.usb.org/sites/default/files/D1T2-2%20-%20USB4%20on%20Windows.pdf
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
