LinuxLists.cc - [PATCH v2] tcpm: During PR_SWAP, source caps should be sent only after tSwapSourceStart

2020-08-12 00:16:24

Subject: [PATCH v2] tcpm: During PR_SWAP, source caps should be sent only after tSwapSourceStart

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 <[email protected]>
---
Changes since V1:
- Comment on the permissible values of tSwapSourceStart
---
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..ed5eed73ccf8 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

2020-08-12 01:44:20

by Guenter Roeck

[permalink] [raw]

Subject: Re: [PATCH v2] tcpm: During PR_SWAP, source caps should be sent only after tSwapSourceStart

On Tue, Aug 11, 2020 at 05:14:39PM -0700, Badhri Jagan Sridharan wrote:
> 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 <[email protected]>

Nit below, otherwise

Reviewed-by: Guenter Roeck <[email protected]>

Note that I wasn't copied on this patch and only noticed it accidentally.

Guenter

> ---
> Changes since V1:
> - Comment on the permissible values of tSwapSourceStart
> ---
> 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..ed5eed73ccf8 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 */

Odd alignment. Same as with the previous two lines which don't use tabs
either.

>
> #define PD_T_DRP_TRY 100 /* 75 - 150 ms */
> #define PD_T_DRP_TRYWAIT 600 /* 400 - 800 ms */

2020-08-12 02:03:38

by Badhri Jagan Sridharan

[permalink] [raw]

Subject: Re: [PATCH v2] tcpm: During PR_SWAP, source caps should be sent only after tSwapSourceStart

On Tue, Aug 11, 2020 at 6:43 PM Guenter Roeck <[email protected]> wrote:
>
> On Tue, Aug 11, 2020 at 05:14:39PM -0700, Badhri Jagan Sridharan wrote:
> > 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 <[email protected]>
>
> Nit below, otherwise
>
> Reviewed-by: Guenter Roeck <[email protected]>
>
> Note that I wasn't copied on this patch and only noticed it accidentally.

Apologies Guenter ! Error on my side while performing the git
send-email command.
Will make sure that I double check next time.

>
> Guenter
>
> > ---
> > Changes since V1:
> > - Comment on the permissible values of tSwapSourceStart
> > ---
> > 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..ed5eed73ccf8 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 */
>
> Odd alignment. Same as with the previous two lines which don't use tabs
> either.
>
> >
> > #define PD_T_DRP_TRY 100 /* 75 - 150 ms */
> > #define PD_T_DRP_TRYWAIT 600 /* 400 - 800 ms */