diff options
| author | Hans de Goede <hdegoede@redhat.com> | 2019-03-16 16:57:12 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-03-19 14:57:31 +0100 |
| commit | 976daf9d1199932df80e7b04546d1a1bd4ed5ece (patch) | |
| tree | 7397ada35aa98305a922f4fdf0b0403e1f7a29a0 /drivers | |
| parent | 40fc165304f0faaae78b761f8ee30b5d216b1850 (diff) | |
usb: typec: tcpm: Try PD-2.0 if sink does not respond to 3.0 source-caps
PD 2.0 sinks are supposed to accept src-capabilities with a 3.0 header and
simply ignore any src PDOs which the sink does not understand such as PPS
but some 2.0 sinks instead ignore the entire PD_DATA_SOURCE_CAP message,
causing contract negotiation to fail.
This commit fixes such sinks not working by re-trying the contract
negotiation with PD-2.0 source-caps messages if we don't have a contract
after PD_N_HARD_RESET_COUNT hard-reset attempts.
The problem fixed by this commit was noticed with a Type-C to VGA dongle.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/typec/tcpm/tcpm.c | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c index 0f62db091d8d..a2233d72ae7c 100644 --- a/drivers/usb/typec/tcpm/tcpm.c +++ b/drivers/usb/typec/tcpm/tcpm.c @@ -37,6 +37,7 @@ S(SRC_ATTACHED), \ S(SRC_STARTUP), \ S(SRC_SEND_CAPABILITIES), \ + S(SRC_SEND_CAPABILITIES_TIMEOUT), \ S(SRC_NEGOTIATE_CAPABILITIES), \ S(SRC_TRANSITION_SUPPLY), \ S(SRC_READY), \ @@ -2966,10 +2967,34 @@ static void run_state_machine(struct tcpm_port *port) /* port->hard_reset_count = 0; */ port->caps_count = 0; port->pd_capable = true; - tcpm_set_state_cond(port, hard_reset_state(port), + tcpm_set_state_cond(port, SRC_SEND_CAPABILITIES_TIMEOUT, PD_T_SEND_SOURCE_CAP); } break; + case SRC_SEND_CAPABILITIES_TIMEOUT: + /* + * Error recovery for a PD_DATA_SOURCE_CAP reply timeout. + * + * PD 2.0 sinks are supposed to accept src-capabilities with a + * 3.0 header and simply ignore any src PDOs which the sink does + * not understand such as PPS but some 2.0 sinks instead ignore + * the entire PD_DATA_SOURCE_CAP message, causing contract + * negotiation to fail. + * + * After PD_N_HARD_RESET_COUNT hard-reset attempts, we try + * sending src-capabilities with a lower PD revision to + * make these broken sinks work. + */ + if (port->hard_reset_count < PD_N_HARD_RESET_COUNT) { + tcpm_set_state(port, HARD_RESET_SEND, 0); + } else if (port->negotiated_rev > PD_REV20) { + port->negotiated_rev--; + port->hard_reset_count = 0; + tcpm_set_state(port, SRC_SEND_CAPABILITIES, 0); + } else { + tcpm_set_state(port, hard_reset_state(port), 0); + } + break; case SRC_NEGOTIATE_CAPABILITIES: ret = tcpm_pd_check_request(port); if (ret < 0) { |