usb: host: xhci: Fix Compliance Mode on SN65LVPE502CP Hardware
This patch is intended to work around a known issue on the SN65LVPE502CP USB3.0 re-driver that can delay the negotiation between a device and the host past the usual handshake timeout. If that happens on the first insertion, the host controller port will enter in Compliance Mode and NO port status event will be generated (as per xHCI Spec) making impossible to detect this event by software. The port will remain in compliance mode until a warm reset is applied to it. As a result of this, the port will seem "dead" to the user and no device connections or disconnections will be detected. For solving this, the patch creates a timer which polls every 2 seconds the link state of each host controller's port (this by reading the PORTSC register) and recovers the port by issuing a Warm reset every time Compliance mode is detected. If a xHC USB3.0 port has previously entered to U0, the compliance mode issue will NOT occur only until system resumes from sleep/hibernate, therefore, the compliance mode timer is stopped when all xHC USB 3.0 ports have entered U0. The timer is initialized again after each system resume. Since the issue is being caused by a piece of hardware, the timer will be enabled ONLY on those systems that have the SN65LVPE502CP installed (this patch uses DMI strings for detecting those systems) therefore making this patch to act as a quirk (XHCI_COMP_MODE_QUIRK has been added to the xhci stack). This patch applies for these systems: Vendor: Hewlett-Packard. System Models: Z420, Z620 and Z820. This patch should be backported to kernels as old as 3.2, as that was the first kernel to support warm reset. The kernels will need to contain both commit 10d674a8 "USB: When hot reset for USB3 fails, try warm reset" and commit 8bea2bd3 "usb: Add support for root hub port status CAS". The first patch add warm reset support, and the second patch modifies the USB core to issue a warm reset when the port is in compliance mode. Signed-off-by: NAlexis R. Cortes <alexis.cortes@ti.com> Signed-off-by: NSarah Sharp <sarah.a.sharp@linux.intel.com> Cc: stable@vger.kernel.org
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