Hi On 19.6.2019 22.03, Rob Weber wrote:
Hi Mathias, I am working on running our custom USB dual-role product through some compliance testing. It seems that the SoC and host controller are not responding to the LFPS signaling and timeout that is supposed to automatically begin the compliance test sequence. I'm currently running a 4.9.115 kernel, and I'm afraid I might be missing some critical patches for compliance test support. I noticed these two patches came up in a google search: https://patchwork.kernel.org/patch/10415345/ https://www.spinics.net/lists/linux-usb/msg160002.html Besides these patches, is there anything else that comes to mind that I might need to do to start compliance testing? I'm about to build a more recent kernel to see if that improves my situation as well.
If xHC hw has a "Compliance Transition Capability" (CTC) bit set in the HCCPARAMS2 register then ports won't go to compliance unless software specifically allows it. see xhci spec section 4.19.1.2.4.1 for more details. Compliance can be allowed either with a SetPortFeature(PORT_LINK_STATE) request, or via debugfs. To allow compliance using debugfs, first check port is in disabled state: # cat /sys/kernel/debug/usb/xhci/0000:00:15.0/ports/port01/portsc Powered Not-connected Disabled Link:RxDetect PortSpeed:0 Change: Wake: enable compliance by writing "compliance" to the port: # echo compliance > /sys/kernel/debug/usb/xhci/0000:00:15.0/ports/port01/portsc This needs to be done for that specific port, and after every port warm reset. After 1st LFPS timeout the port should go to compliance, can be read from portsc Also make sure you don't have XHCI_COMP_MODE_QUIRK or XHCI_MISSING_CAS quirks set, these try to recover ports that accidentally enter compliance mode in normal use.
Just for reference, our product uses an intel atom z8550 SoC that uses an xHCI host controller and a dwc3 device controller. Our platform also uses a USB 3.0 redriver. The datasheet for this redriver (tusb542) indicates that it's internal LFPS controller supports full USB 3.0 compliance requirements.
z8550 is Cherry Trail? I unfortunately don't have those around anymore. -Mathias
