[PATCH 0/2] usb: fix ASM3242 reporting SuperSpeed for a Gen 2x2 link

[Kean Ren <rh_king@163.com>]

The ASMedia ASM3242 (1b21:3242) reports the SuperSpeed speed ID together
with two active lanes for a link that is actually running at USB 3.2
Gen 2x2 after a cold boot.  Linux therefore classifies the device as
USB 3.0 SuperSpeed and reports 5000M/x2, although the measured
throughput is 1.49-1.60 GB/s (11.9-12.8 Gbps), which is above the
physical ceiling of a 10 Gbps link (~1.25 GB/s).

  Patch 1 is a generic correctness fix: get_port_ssp_rate() currently
  cannot recognise USB 3.2 Gen 1x2 at all, because it rejects any
  matching sublink entry whose link protocol is not SuperSpeedPlus
  before it looks at the number of active lanes.

  Patch 2 adds a controller quirk so that this hardware reports the
  Gen 2x2 speed ID.  The raw extended port status, the measured
  throughput and the list of resets that do and do not restore the
  correct report are all in the patch description.

The wrong report is 100% reproducible after every reboot and is only
cleared by an S3 suspend/resume.  Raw data (lsusb -v, lspci -vv, sysfs
and BOS dumps, kernel log) is available on request.

Kean Ren (2):
  usb: core: hub: recognise two-lane SuperSpeed sublinks as Gen 1x2
  xhci: fix ASM3242 port speed report for Gen 2x2 links after cold boot

 drivers/usb/core/hub.c      | 30 ++++++++++++++++++++----------
 drivers/usb/host/xhci-hub.c | 17 +++++++++++++++--
 drivers/usb/host/xhci-pci.c |  4 ++++
 drivers/usb/host/xhci.h     |  1 +
 4 files changed, 40 insertions(+), 12 deletions(-)