Hi Guenter,
> -----Original Message-----
> From: Guenter Roeck <groeck7@xxxxxxxxx> On Behalf Of Guenter Roeck
> Sent: Wednesday, February 15, 2023 11:27 PM
> To: Xu Yang <xu.yang_2@xxxxxxx>; heikki.krogerus@xxxxxxxxxxxxxxx
> Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx; dl-linux-imx <linux-imx@xxxxxxx>; Jun Li <jun.li@xxxxxxx>
> Subject: [EXT] Re: [PATCH] usb: typec: tcpm: fix warning when handle discover_identity message
>
> Caution: EXT Email
>
> On 2/15/23 03:31, Xu Yang wrote:
> > Since both source and sink device can send discover_identity message in
> > PD3, kernel may dump below warning:
> >
> > ------------[ cut here ]------------
> > WARNING: CPU: 0 PID: 169 at drivers/usb/typec/tcpm/tcpm.c:1446 tcpm_queue_vdm+0xe0/0xf0
> > Modules linked in:
> > CPU: 0 PID: 169 Comm: 1-0050 Not tainted 6.1.1-00038-g6a3c36cf1da2-dirty #567
> > Hardware name: NXP i.MX8MPlus EVK board (DT)
> > pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> > pc : tcpm_queue_vdm+0xe0/0xf0
> > lr : tcpm_queue_vdm+0x2c/0xf0
> > sp : ffff80000c19bcd0
> > x29: ffff80000c19bcd0 x28: 0000000000000001 x27: ffff0000d11c8ab8
> > x26: ffff0000d11cc000 x25: 0000000000000000 x24: 00000000ff008081
> > x23: 0000000000000001 x22: 00000000ff00a081 x21: ffff80000c19bdbc
> > x20: 0000000000000000 x19: ffff0000d11c8080 x18: ffffffffffffffff
> > x17: 0000000000000000 x16: 0000000000000000 x15: ffff0000d716f580
> > x14: 0000000000000001 x13: ffff0000d716f507 x12: 0000000000000001
> > x11: 0000000000000000 x10: 0000000000000020 x9 : 00000000000ee098
> > x8 : 00000000ffffffff x7 : 000000000000001c x6 : ffff0000d716f580
> > x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
> > x2 : ffff80000c19bdbc x1 : 00000000ff00a081 x0 : 0000000000000004
> > Call trace:
> > tcpm_queue_vdm+0xe0/0xf0
> > tcpm_pd_rx_handler+0x340/0x1ab0
> > kthread_worker_fn+0xcc/0x18c
> > kthread+0x10c/0x110
> > ret_from_fork+0x10/0x20
> > ---[ end trace 0000000000000000 ]---
> >
> > Below sequences may trigger this warning:
> >
> > tcpm_send_discover_work(work)
> > tcpm_send_vdm(port, USB_SID_PD, CMD_DISCOVER_IDENT, NULL, 0);
> > tcpm_queue_vdm(port, header, data, count);
> > port->vdm_state = VDM_STATE_READY;
> >
> > vdm_state_machine_work(work);
> > <-- received discover_identity from partner
> > vdm_run_state_machine(port);
> > port->vdm_state = VDM_STATE_SEND_MESSAGE;
> > mod_vdm_delayed_work(port, x);
> >
> > tcpm_pd_rx_handler(work);
> > tcpm_pd_data_request(port, msg);
> > tcpm_handle_vdm_request(port, msg->payload, cnt);
> > tcpm_queue_vdm(port, response[0], &response[1], rlen - 1);
> > --> WARN_ON(port->vdm_state > VDM_STATE_DONE);
> >
> > For this case, since the state machine could still send out discover
> > identity message later if we skip current discover_identity message.
>
> the second part of "since" is missing. since ... what ?
>
> If this is supposed to be "since ... we should handle", just drop the
> "since".
Okay.
>
> > So we should handle the received message firstly and override the pending
> > discover_identity message without warning in this case. Then, a delayed
> > send_discover work will send discover_identity message again.
> >
> > Fixes: e00943e91678 ("usb: typec: tcpm: PD3.0 sinks can send Discover Identity even in device mode")
> > cc: <stable@xxxxxxxxxxxxxxx>
> > Signed-off-by: Xu Yang <xu.yang_2@xxxxxxx>
> > ---
> > drivers/usb/typec/tcpm/tcpm.c | 18 +++++++++++++++---
> > 1 file changed, 15 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> > index 7f39cb9b3429..914bbaf4e25e 100644
> > --- a/drivers/usb/typec/tcpm/tcpm.c
> > +++ b/drivers/usb/typec/tcpm/tcpm.c
> > @@ -1445,10 +1445,19 @@ static int tcpm_ams_start(struct tcpm_port *port, enum tcpm_ams ams)
> > static void tcpm_queue_vdm(struct tcpm_port *port, const u32 header,
> > const u32 *data, int cnt)
> > {
> > + u32 vdo_hdr = port->vdo_data[0];
> > +
> > WARN_ON(!mutex_is_locked(&port->lock));
> >
> > - /* Make sure we are not still processing a previous VDM packet */
> > - WARN_ON(port->vdm_state > VDM_STATE_DONE);
> > + /* If is sending discover_identity, handle received message firstly */
>
> firstly -> first
Okay.
>
> > + if (PD_VDO_SVDM(vdo_hdr) &&
> > + PD_VDO_CMD(vdo_hdr) == CMD_DISCOVER_IDENT) {
> > + port->send_discover = true;
> > + mod_send_discover_delayed_work(port,
> > + SEND_DISCOVER_RETRY_MS);
> > + } else
> > + /* Make sure we are not still processing a previous VDM packet */
> > + WARN_ON(port->vdm_state > VDM_STATE_DONE);
> >
> > port->vdo_count = cnt + 1;
> > port->vdo_data[0] = header;
> > @@ -1950,9 +1959,11 @@ static void vdm_run_state_machine(struct tcpm_port *port)
> > res = tcpm_ams_start(port, DISCOVER_IDENTITY);
> > if (res == 0)
> > port->send_discover = false;
> > - else if (res == -EAGAIN)
> > + else if (res == -EAGAIN) {
> > + port->vdo_data[0] = 0;
> > mod_send_discover_delayed_work(port,
> > SEND_DISCOVER_RETRY_MS);
> > + }
>
>
> Both sides of if/else should have braces.
Will change.
>
> > break;
> > case CMD_DISCOVER_SVID:
> > res = tcpm_ams_start(port, DISCOVER_SVIDS);
> > @@ -2035,6 +2046,7 @@ static void vdm_run_state_machine(struct tcpm_port *port)
> > unsigned long timeout;
> >
> > port->vdm_retries = 0;
> > + port->vdo_data[0] = 0;
> > port->vdm_state = VDM_STATE_BUSY;
> > timeout = vdm_ready_timeout(vdo_hdr);
> > mod_vdm_delayed_work(port, timeout);
Thanks,
Xu Yang
