On 2/15/23 19:15, 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, the state machine could still send out discover
identity message later if we skip current discover_identity message.
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>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
Changelogs:
v2: modify some code format and commit message
---
drivers/usb/typec/tcpm/tcpm.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 7f39cb9b3429..1ee774c263f0 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -1445,10 +1445,18 @@ 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 first */
+ 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;
@@ -1948,11 +1956,13 @@ static void vdm_run_state_machine(struct tcpm_port *port)
switch (PD_VDO_CMD(vdo_hdr)) {
case CMD_DISCOVER_IDENT:
res = tcpm_ams_start(port, DISCOVER_IDENTITY);
- if (res == 0)
+ 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);
+ }
break;
case CMD_DISCOVER_SVID:
res = tcpm_ams_start(port, DISCOVER_SVIDS);
@@ -2035,6 +2045,7 @@ 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);
