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Subject[PATCH 1/2 v3] tcpm: During PR_SWAP, source caps should be sent only after tSwapSourceStart
From
From the spec:
"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."

This fixes TD.PD.CP.E3, TD.PD.CP.E4, TD.PD.CP.E5 failures

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
---
Changes since V1:
- Comment on the permissible values of tSwapSourceStart

Changes since V2:
- Fixing alignment issue pointed out by Guenter.
- Added Reviewed-by: Guenter Roeck <linux@roeck-us.net>
---
drivers/usb/typec/tcpm/tcpm.c | 2 +-
include/linux/usb/pd.h | 1 +
2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 3ef37202ee37..d38347bd3335 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -3555,7 +3555,7 @@ static void run_state_machine(struct tcpm_port *port)
*/
tcpm_set_pwr_role(port, TYPEC_SOURCE);
tcpm_pd_send_control(port, PD_CTRL_PS_RDY);
- tcpm_set_state(port, SRC_STARTUP, 0);
+ tcpm_set_state(port, SRC_STARTUP, PD_T_SWAP_SRC_START);
break;

case VCONN_SWAP_ACCEPT:
diff --git a/include/linux/usb/pd.h b/include/linux/usb/pd.h
index b6c233e79bd4..1df895e4680b 100644
--- a/include/linux/usb/pd.h
+++ b/include/linux/usb/pd.h
@@ -473,6 +473,7 @@ static inline unsigned int rdo_max_power(u32 rdo)
#define PD_T_ERROR_RECOVERY 100 /* minimum 25 is insufficient */
#define PD_T_SRCSWAPSTDBY 625 /* Maximum of 650ms */
#define PD_T_NEWSRC 250 /* Maximum of 275ms */
+#define PD_T_SWAP_SRC_START 20 /* Minimum of 20ms */

#define PD_T_DRP_TRY 100 /* 75 - 150 ms */
#define PD_T_DRP_TRYWAIT 600 /* 400 - 800 ms */
--
2.28.0.236.gb10cc79966-goog
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