On Thu, Aug 13, 2020 at 12:40:04PM -0700, Badhri Jagan Sridharan wrote: > Hi Heikki, > > Sure. Same as the other patch I will try to address your question here > and will update the commit description once you are satisfied with the > description. > > Subject: > During PR_SWAP, source caps should be sent only after tSwapSourceStart > > Commit description: > The patch addresses the compliance test failures while running > TD.PD.CP.E3, TD.PD.CP.E4, TD.PD.CP.E5 of the "Deterministic PD > Compliance MOI" test plan published in https://www.usb.org/usbc. > For a product to be Type-C compliant, it's expected that these tests > are run on usb.org certified Type-C compliance tester as mentioned in > https://www.usb.org/usbc. > > The purpose of the tests TD.PD.CP.E3, TD.PD.CP.E4, TD.PD.CP.E5 is to > verify the PR_SWAP response of the device. While doing so, the test > asserts that Source Capabilities message is NOT received from the test > device within tSwapSourceStart min (20 ms) from the time the last bit > of GoodCRC corresponding to the RS_RDY message sent by the UUT was > sent. If it does then the test fails. > > This is in line with the requirements from the USB Power Delivery > Specification Revision 3.0, Version 1.2: > "6.6.8.1 SwapSourceStartTimer > The SwapSourceStartTimer Shall be used by the new Source, after a > Power Role Swap or Fast Role Swap, to ensure that it does not send > Source_Capabilities Message before the new Sink is ready to receive > the > Source_Capabilities Message. The new Source Shall Not send the > Source_Capabilities Message earlier than tSwapSourceStart after the > last bit of the EOP of GoodCRC Message sent in response to the PS_RDY > Message sent by the new Source indicating that its power supply is > ready." > > The patch makes sure that TCPM does not send the Source_Capabilities > Message within tSwapSourceStart(20ms) by transitioning into > SRC_STARTUP only after tSwapSourceStart(20ms). That looks good to me. Thanks. Br, -- heikki