Date: Thu, 5 Sep 2024 08:53:30 +0300
From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Mario Limonciello <mario.limonciello@amd.com>
Cc: Mathias Nyman <mathias.nyman@linux.intel.com>,
	linux-usb@vger.kernel.org, "Rangoju, Raju" <Raju.Rangoju@amd.com>,
	Sanath S <Sanath.S@amd.com>, gregkh@linuxfoundation.org
Subject: Re: [PATCH v2 0/4] Add device links between tunneled USB3 devices
 and USB4 Host
Message-ID: <20240905055330.GH1532424@black.fi.intel.com>
References: <20240830152630.3943215-1-mathias.nyman@linux.intel.com>
 <321cf204-cf74-4f51-8ed3-8c5738444359@amd.com>
 <20240904050013.GZ1532424@black.fi.intel.com>
 <7a3fc5cd-1705-40ab-8d93-d9f286009aa7@amd.com>
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On Wed, Sep 04, 2024 at 12:38:15PM -0500, Mario Limonciello wrote:
> ❯ ls -l /sys/bus/pci/drivers/thunderbolt/*/consumer*
> lrwxrwxrwx 1 root root 0 Sep  4 12:33
> /sys/bus/pci/drivers/thunderbolt/0000:c4:00.5/consumer:pci:0000:00:03.1 ->
> ../../../virtual/devlink/pci:0000:c4:00.5--pci:0000:00:03.1/
> lrwxrwxrwx 1 root root 0 Sep  4 12:33
> /sys/bus/pci/drivers/thunderbolt/0000:c4:00.6/consumer:pci:0000:00:04.1 ->
> ../../../virtual/devlink/pci:0000:c4:00.6--pci:0000:00:04.1/
> ❯ cat /sys/bus/pci/drivers/thunderbolt/*/power/runtime_status
> suspended
> active
> 
> I would have expected the USB4 host router to go back into runtime PM, but
> it doesn't anymore until I reboot the system.

Yes, it should enter runtime suspend after a while. Would you mind
sharing dmesg around this?

I tried on my system and it works as expected (the device-power.sh is
internal script that dumps the device power states, I can share if you
want).

Devices 0d.2/3 are the host routers. 07.[0-3] are the PCIe tunnels (not
really used here but shown for completeness, I don't have PCIe tunnel
enabled to the hub). 0d.0 is the xHCI controller.

Plug in USB4 hub
----------------

# device-power.sh -s
All PCI devices (software state)
...
0000:00:07.0 8086:7ec4 Status: [D3cold] Real status: [    D0] Runtime PM: [suspended]
0000:00:07.1 8086:7ec5 Status: [D3cold] Real status: [    D0] Runtime PM: [suspended]
0000:00:07.2 8086:7ec6 Status: [D3cold] Real status: [    D0] Runtime PM: [suspended]
0000:00:07.3 8086:7ec7 Status: [D3cold] Real status: [    D0] Runtime PM: [suspended]
...
0000:00:0d.0 8086:7ec0 Status: [D3cold] Real status: [    D0] Runtime PM: [suspended]
0000:00:0d.2 8086:7ec2 Status: [    D0] Real status: [    D0] Runtime PM: [   active]
0000:00:0d.3 8086:7ec3 Status: [    D0] Real status: [    D0] Runtime PM: [   active]

Unplug and wait for the autosuspend_delay
-----------------------------------------

# device-power.sh -s
All PCI devices (software state)
...
0000:00:07.0 8086:7ec4 Status: [D3cold] Real status: [D3cold] Runtime PM: [suspended]
0000:00:07.1 8086:7ec5 Status: [D3cold] Real status: [D3cold] Runtime PM: [suspended]
0000:00:07.2 8086:7ec6 Status: [D3cold] Real status: [D3cold] Runtime PM: [suspended]
0000:00:07.3 8086:7ec7 Status: [D3cold] Real status: [D3cold] Runtime PM: [suspended]
...
0000:00:0d.0 8086:7ec0 Status: [D3cold] Real status: [D3cold] Runtime PM: [suspended]
0000:00:0d.2 8086:7ec2 Status: [D3cold] Real status: [D3cold] Runtime PM: [suspended]
0000:00:0d.3 8086:7ec3 Status: [D3cold] Real status: [D3cold] Runtime PM: [suspended]