linux.git/drivers/thunderbolt/tb.c, branch v6.0

thunderbolt: Change TMU mode to HiFi uni-directional once DisplayPort tunneled

2022-06-06T09:24:56+00:00

Here we configure TMU mode to HiFi uni-directional once DP tunnel
is created. This is due to accuracy requirement for DP tunneling
as appears in CM guide 1.0, section 7.3.2.
Due to Intel hardware limitation, once we changed the TMU mode to HiFi
uni-directional (when DP tunnel exists), we don't change TMU mode back to
normal uni-directional, even if DP tunnel is torn down later.

Signed-off-by: Gil Fine 
Signed-off-by: Mika Westerberg

thunderbolt: Add CL1 support for USB4 and Titan Ridge routers

2022-06-06T09:24:56+00:00

In this patch we add support for a second low power state of the link: CL1.
Low power states (called collectively CLx) are used to reduce
transmitter and receiver power when a high-speed lane is idle.
We enable it, if both sides of the link support it,
and only for the first hop router (i.e. the first device that connected
to the host router). This is needed for better thermal management.

Signed-off-by: Gil Fine 
Signed-off-by: Mika Westerberg

thunderbolt: Silently ignore CLx enabling in case CLx is not supported

2022-06-06T09:19:22+00:00

We can't enable CLx if it is not supported either by the host or device,
or by the USB4/TBT link (e.g. when an optical cable is used).
We silently ignore CLx enabling in this case.

Signed-off-by: Gil Fine 
Signed-off-by: Mika Westerberg

thunderbolt: Add support for XDomain lane bonding

2022-05-05T06:25:23+00:00

The USB4 Inter-Domain Service specification defines a protocol that can
be used to establish lane bonding between two USB4 domains (hosts). So
far we have not implemented it because the host controller DMA was not
fast enough to be able to go over 20 Gbits/s even if lanes were bonded.
However, starting from Intel Alder Lake CPUs the DMA can go over
20 Gbits/s so now it makes more sense to add this support to the driver.

Because both ends need to negotiate the bonding we add a simple state
machine that tracks the connection state and does the necessary steps
described by the USB4 Inter-Domain Service specification. We only
establish lane bonding when both sides of the link support it. Otherwise
we default to use the single lane. Also this is only done when software
connection manager is used. On systems with firmware based connection
manager, it handles the high-speed tunneling so bonding lanes is
specific to the implementation (Intel firmware based connection manager
does not support lane bonding).

Signed-off-by: Mika Westerberg

thunderbolt: Use different lane for second DisplayPort tunnel

2022-04-19T07:26:18+00:00

Brad reported that on Apple hardware with Light Ridge or Falcon Ridge
controller, plugging in a chain of Thunderbolt displays (Light Ridge
based controllers) causes all kinds of tearing and flickering. The
reason for this is that on Thunderbolt 1 hardware there is no lane
bonding so we have two independent 10 Gb/s lanes, and currently Linux
tunnels both displays through the lane 1. This makes the displays to
share the 10 Gb/s bandwidth which may not be enough for higher
resolutions.

For this reason make the second tunnel go through the lane 0 instead.
This seems to match what the macOS connection manager is also doing.

Reported-by: Brad Campbell 
Signed-off-by: Mika Westerberg 
Tested-by: Brad Campbell

thunderbolt: Add internal xHCI connect flows for Thunderbolt 3 devices

2022-02-02T10:56:51+00:00

Both Alpine Ridge and Titan Ridge require special flows in order to
activate the internal xHCI controller when there is USB device connected
to the downstream type-C port. This implements the missing flows for
both.

Signed-off-by: Mika Westerberg

thunderbolt: Enable CL0s for Intel Titan Ridge

2021-12-28T07:43:56+00:00

Low power link states (called collectively CLx) are used to reduce
transmitter and receiver power when a high-speed lane is idle. The
simplest one being called CL0s. Follow what we already do for USB4
device routers and enable CL0s for Intel Titan Ridge device router too.
This allows better thermal management.

Signed-off-by: Gil Fine 
Signed-off-by: Mika Westerberg

thunderbolt: Add CL0s support for USB4 routers

2021-12-22T14:13:14+00:00

In this patch we add enabling of CL0s - a low power state of the link.
Low power states (called collectively CLx) are used to reduce
transmitter and receiver power when a high-speed lane is idle. For now,
we add support only for first low power state: CL0s.  We enable it, if
both sides of the link support it, and only for the first hop router.
(i.e. the first device that connected to the host router). This is
needed for better thermal management.

Signed-off-by: Gil Fine 
Signed-off-by: Mika Westerberg

thunderbolt: Add TMU uni-directional mode

2021-12-22T14:13:14+00:00

Up until Titan Ridge (Thunderbolt 3) device routers only supported
bi-directional mode. In this patch we add to TMU a uni-directional mode.
The uni-directional mode is needed for enabling of low power state of
the link (CLx).

Signed-off-by: Gil Fine 
Signed-off-by: Mika Westerberg

thunderbolt: Tear down existing tunnels when resuming from hibernate

2021-12-07T12:18:33+00:00

If the boot firmware implements connection manager of its own it may not
create the paths in the same way or order we do. For example it may
create first PCIe tunnel and then USB3 tunnel. When we restore our
tunnels (first de-activating them) we may be doing that over completely
different tunnels and that leaves them possibly non-functional. For this
reason we re-use the tunnel discovery functionality and find out all the
existing tunnels, and tear them down. Once that is done we can restore
our tunnels.

Signed-off-by: Mika Westerberg