Comment 0 for bug 1928242

[SRU Justification]

[Impact]
All of 3 different WD19(TB/SC/DC) docks have 3 Type-A ports and 2 Type-C ports, and there're highspeed Hubs(0bda:5487 and its substream hub 0bda:5413) and Superspeed Hubs (0bda:0413 and its downstream hub 0bda:5413). In the bug description below, we will refer the 2 highspeed hubs as Hub A and Hub A.3, and the 2 superspeed hubs as Hub B and Hub B.3. All devices connected via either Type-A or Type-C ports will connect to either Hub A.3 or Hub B.3. If we connect a wakup enabled device (keyboard) to a Type-A port, the Hub A.3 will fail to activate after exiting s2idle and all downstream devices will not be detected. If we have a superspeed device connected to other Type-A port in addition to the keyboard, this superspeed device actually connects to Hub B.3, and the Hub B.3 will also fails to work after exiting s2idle. If the wakeup enabled device connects via Type-C port, there's no such problem.

As a summary, a wakeup enabled device connect to Type-A port will cause the failure of Hub A.3 and Hub B.3. Hub B.3 only fails when a wakeup enabled device and a superspeed device both connect via Type-A port.

[Fix]
Before the resume failure, the upstream hub(Hub A or B) will hit the timeout problem while doing SetPortFeature(PORT_SUSPEND) to the port of the downstream hub (Hub A.3 or Hub B.3). However, the PORT_SUSPEND bit of the wPortStatus is actually turned on for the Hub A.3, we simply need to make the kernel believe it's already suspended. Then the ClearPortFeature will be done during resume and the problem will go away.

The Hub B.3 will be tricky. The PORT_SUSPEND bit is not on after the suspend timeout, but we need to reset_resume the Hub B.3 to avoid resume failure. It's hard to create a generic fix for it. Because it only happens when timeout happens on suspending Hub A.3 and there's a superspeed device connecting to Type-A port. I can only reset_resume the problematic hub if the timeout happens during suspend and it happens to be a Realtek hub.

[Test]
1. Make sure that the WD19 connects to the laptop
2. Connect a USB keyboard and a superspeed USB stick to USB Type-A ports.
3. Suspend the system
4. Press the Enter key or power button to wake up the system
5. Check if the keyboard and USB stick are still working
Repeat 4 and 5 for > 10 times w/o losing any USB devices.

[Where problems could occur]
A wakeup enabled device (keyboard) connect to Type-A port will cause the failure of Hub A.3 and Hub B.3 during resume. Hub B.3 only fails when a wakeup enabled device and a superspeed device both connect via Type-A port. All devices connects to Hub A.3 (and B.3 if superspeed device connect via Type-A port) will be lost after resume.

[Regression Potential]
Minimum. The fix is only triggered when timeout happens during USB port suspend and it follows the standard USB protocol to do either resume or reset_resume.

========== Original Bug Description ==========

● Summary
Plug in USB mouse and USB keyboard to WD19/WD19DC USB ports near LAN port. Plug dock into SUT and check USB keyboard and mouse work. SUT enter suspend. After 1 min resume SUT, check USB keyboard/mouse function. Sometimes USB keyboard/mouse no function.

Isolation:
1. VP on UMA and Discrete
2. When issue occur, both front and back port on WD19 can't work using USB keyboard/mouse but USB Key.

● Reproduce Steps
1.Plug in USB mouse and USB keyboard to WD19/WD19DC USB ports near LAN port.
2.Plug dock into SUT and check USB keyboard and mouse work.
3. SUT enter suspend.
4.After 1 min, resume SUT and check USB keyboard/mouse function.
5.Sometimes USB keyboard/mouse no function.

● Results
○ Expected Result
USB mouse or keyboard on dock can use after suspend

○ Actual Result
USB mouse or keyboard on dock sometimes no function after suspend

● Additional Information
○ Test Vault ID：60943.011
○ SKU：Broadmoor Latitude5421
○ BIOS Version：0.3.21
○ Image/Manifest：
dell-bto-focal-fossa-pidgeot-14-X79-20210106-3.iso
dell-bto-focal-fossa-pidgeot-14-X81-20210121-6.iso
○ CPU：TGL ES
○ GPU：Intel pGFX 2020
○ Failure rate：F/R: 2/2 units, 1/10 times
○ WD19 dock, Dock DFU: 1.0.15