forked from Minki/linux
mainlining shenanigans
02d5be466b
According to the spec the following is the condition for exiting TryWait.SRC: "The port shall transition to Attached.SRC when V BUS is at vSafe0V and the SRC.Rd state is detected on exactly one of the CC pins for at least tCCDebounce. The port shall transition to Unattached.SNK after tDRPTry if neither of the CC1 or CC2 pins are in the SRC.Rd state" TCPM at present keeps re-entering the SRC_TRYWAIT and keeps restarting tDRPTry if the CC presents Rp and disconnects within tCCDebounce. For example: [ 447.164308] pending state change SRC_TRYWAIT -> SRC_ATTACHED @ 200 ms [ 447.164386] CC1: 2 -> 0, CC2: 0 -> 0 [state SRC_TRYWAIT, polarity 0, disconnected] [ 447.164406] state change SRC_TRYWAIT -> SRC_TRYWAIT [ 447.164573] cc:=3 [ 447.191408] pending state change SRC_TRYWAIT -> SRC_TRYWAIT_UNATTACHED @ 100 ms [ 447.191478] CC1: 0 -> 0, CC2: 0 -> 0 [state SRC_TRYWAIT, polarity 0, disconnected] [ 447.207261] CC1: 0 -> 2, CC2: 0 -> 0 [state SRC_TRYWAIT, polarity 0, connected] [ 447.207306] state change SRC_TRYWAIT -> SRC_TRYWAIT [ 447.207485] cc:=3 [ 447.237283] pending state change SRC_TRYWAIT -> SRC_ATTACHED @ 200 ms [ 447.237357] CC1: 2 -> 0, CC2: 0 -> 0 [state SRC_TRYWAIT, polarity 0, disconnected] [ 447.237379] state change SRC_TRYWAIT -> SRC_TRYWAIT [ 447.237532] cc:=3 [ 447.263219] pending state change SRC_TRYWAIT -> SRC_TRYWAIT_UNATTACHED @ 100 ms [ 447.263289] CC1: 0 -> 0, CC2: 0 -> 0 [state SRC_TRYWAIT, polarity 0, disconnected] [ 447.280926] CC1: 0 -> 2, CC2: 0 -> 0 [state SRC_TRYWAIT, polarity 0, connected] [ 447.280970] state change SRC_TRYWAIT -> SRC_TRYWAIT [ 447.281158] cc:=3 [ 447.307767] pending state change SRC_TRYWAIT -> SRC_ATTACHED @ 200 ms [ 447.307838] CC1: 2 -> 0, CC2: 0 -> 0 [state SRC_TRYWAIT, polarity 0, disconnected] [ 447.307858] state change SRC_TRYWAIT -> SRC_TRYWAIT In TCPM, tDRPTry is set tp 100ms (min 75ms and max 150ms) and tCCdebounce is set to 200ms (min 100ms and max 200ms). To overcome the issue, record the time at which the port enters TryWait.SRC(SRC_TRYWAIT) and re-enter SRC_TRYWAIT only when CC keeps debouncing within tDRPTry. Signed-off-by: Badhri Jagan Sridharan <Badhri@google.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.