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SubjectRe: [PATCH] usb: typec: tcpm: Fix altmode re-registration causes sysfs create fail
From
On 12/15/22 17:21, cy_huang wrote:
> From: ChiYuan Huang <cy_huang@richtek.com>
>
> There's the altmode re-registeration issue after data role
> swap (DR_SWAP).
>
> Comparing to USBPD 2.0, in USBPD 3.0, it loose the limit that only DFP
> can initiate the VDM command to get partner identity information.
>
> For a USBPD 3.0 UFP device, it may already get the identity information
> from its port partner before DR_SWAP. If DR_SWAP send or receive at the
> mean time, 'send_discover' flag will be raised again. It causes discover
> identify action restart while entering ready state. And after all
> discover actions are done, the 'tcpm_register_altmodes' will be called.
> If old altmode is not unregistered, this sysfs create fail can be found.
>
> In 'DR_SWAP_CHANGE_DR' state case, only DFP will unregister altmodes.
> For UFP, the original altmodes keep registered.
>
> This patch fix the logic that after DR_SWAP, 'tcpm_unregister_altmodes'
> must be called whatever the current data role is.
>
> Fixes: ae8a2ca8a221 ("usb: typec: Group all TCPCI/TCPM code together)
> Reported-by: TommyYl Chen <tommyyl.chen@mediatek.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
> ---
> Hi,
>
> Below's the issue log for the reference.
>
> *TCPM
> [ 3.856679] AMS DISCOVER_MODES start
> [ 3.856687] PD TX, header: 0x188f
> [ 3.858827] PD TX complete, status: 0
> [ 3.865330] PD RX, header: 0x2daf [1]
> [ 3.865340] Rx VDM cmd 0xff01a043 type 1 cmd 3 len 2
> [ 3.865348] AMS DISCOVER_MODES finished
> [ 3.865352] Alternate mode 0: SVID 0xff01, VDO 1: 0x001c0045
> [ 3.865362] AMS DISCOVER_MODES start
> [ 3.865367] PD TX, header: 0x1a8f
> [ 3.867802] PD TX complete, status: 0
> [ 3.875208] PD RX, header: 0x2faf [1]
> [ 3.875216] Rx VDM cmd 0x413ca043 type 1 cmd 3 len 2
> [ 3.875222] AMS DISCOVER_MODES finished
> [ 3.875225] Alternate mode 1: SVID 0x413c, VDO 1: 0x00000001
> [ 3.938243] AMS GET_SINK_CAPABILITIES start
> [ 3.938255] state change SNK_READY -> AMS_START [rev3 GET_SINK_CAPABILITIES]
> [ 3.938266] state change AMS_START -> GET_SINK_CAP [rev3 GET_SINK_CAPABILITIES]
> [ 3.938274] PD TX, header: 0xe88
> [ 3.940268] PD TX complete, status: 0
> [ 3.940310] pending state change GET_SINK_CAP -> GET_SINK_CAP_TIMEOUT @ 60 ms
> [rev3 GET_SINK_CAPABILITIES]
> [ 3.946291] PD RX, header: 0x13a4 [1]
> [ 3.946295] Port partner FRS capable partner_frs_current:0 port_frs_current:0 enable:n
> [ 3.946298] state change GET_SINK_CAP -> SNK_READY [rev3 GET_SINK_CAPABILITIES]
> [ 3.946304] AMS GET_SINK_CAPABILITIES finished
> [ 4.239342] CC1: 5 -> 4, CC2: 0 -> 0 [state SNK_READY, polarity 0, connected]
> [ 4.256594] PD RX, header: 0x5a9 [1]
> [ 4.256603] state change SNK_READY -> DR_SWAP_ACCEPT [rev3 DATA_ROLE_SWAP]
> [ 4.256609] PD TX, header: 0x83
> [ 4.258528] PD TX complete, status: 0
> [ 4.258584] state change DR_SWAP_ACCEPT -> DR_SWAP_CHANGE_DR [rev3 DATA_ROLE_SWAP]
> [ 4.258591] Requesting mux state 1, usb-role 1, orientation 1
> [ 4.259588] AMS DATA_ROLE_SWAP finished
> [ 4.259592] state change DR_SWAP_CHANGE_DR -> SNK_READY [rev3 NONE_AMS]
> [ 4.259605] AMS DISCOVER_IDENTITY start
> [ 4.259609] Sink TX No Go
> [ 4.260874] CC1: 4 -> 5, CC2: 0 -> 0 [state SNK_READY, polarity 0, connected]
> [ 4.359636] AMS DISCOVER_IDENTITY start
> [ 4.359642] PD TX, header: 0x12af
> [ 4.361884] PD TX complete, status: 0
> [ 4.369433] PD RX, header: 0x578f [1]
> [ 4.369439] Rx VDM cmd 0xff00a041 type 1 cmd 1 len 5
> [ 4.369448] AMS DISCOVER_IDENTITY finished
> [ 4.369515] Identity: 413c:c013.0712
> [ 4.369521] AMS DISCOVER_SVIDS start
> [ 4.369524] PD TX, header: 0x14af
> [ 4.371696] PD TX complete, status: 0
> [ 4.378564] PD RX, header: 0x398f [1]
> [ 4.378573] Rx VDM cmd 0xff00a042 type 1 cmd 2 len 3
> [ 4.378579] AMS DISCOVER_SVIDS finished
> [ 4.378582] SVID 1: 0xff01
> [ 4.378584] SVID 2: 0x413c
> [ 4.378594] AMS DISCOVER_MODES start
> [ 4.378597] PD TX, header: 0x16af
> [ 4.380696] PD TX complete, status: 0
> [ 4.387008] PD RX, header: 0x2b8f [1]
> [ 4.387014] Rx VDM cmd 0xff01a043 type 1 cmd 3 len 2
> [ 4.387021] AMS DISCOVER_MODES finished
> [ 4.387023] Alternate mode 0: SVID 0xff01, VDO 1: 0x001c0045
> [ 4.387029] AMS DISCOVER_MODES start
> [ 4.387031] PD TX, header: 0x18af
> [ 4.389134] PD TX complete, status: 0
> [ 4.395528] PD RX, header: 0x2d8f [1]
> [ 4.395538] Rx VDM cmd 0x413ca043 type 1 cmd 3 len 2
> [ 4.395546] AMS DISCOVER_MODES finished
> [ 4.395548] Alternate mode 1: SVID 0x413c, VDO 1: 0x00000001
>
> *Kernel TRACE
> sysfs: cannot create duplicate filename
> '/devices/platform/soc/11d01000.i2c/i2c-0/0-0034/mt6360-tcpc.6.auto/typec/port0/port0.0/partner'
> CPU: 2 PID: 299 Comm: mt6360-tcpc.6.a Tainted: GO 5.15.37-mtk+g880abc5122e7 #1
> Hardware name: MediaTek MT8195 demo board (DT)
> Call trace:
> dump_backtrace+0x0/0x1ac
> show_stack+0x24/0x30
> dump_stack_lvl+0x68/0x84
> dump_stack+0x1c/0x38
> sysfs_warn_dup+0x70/0x90
> typec_probe+0xa4/0x134 [typec]
> really_probe.part.0+0xa4/0x310
> __device_attach_driver+0x100/0x16c
> bus_for_each_drv+0x84/0xe0
> __device_attach+0xe0/0x1ac
> device_add+0x39c/0x8b0
> device_register+0x2c/0x40
> typec_register_altmode+0x1f4/0x360 [typec]
> typec_partner_register_altmode+0x1c/0x30 [typec]
> tcpm_pd_rx_handler+0x19d4/0x1c0c [tcpm]
> kthread_worker_fn+0xb8/0x290
> kthread+0x15c/0x170
> ret_from_fork+0x10/0x20
> [ 4.395962] typec_displayport port0-partner.2: failed to create symlinks
> [ 4.395967] typec_displayport: probe of port0-partner.2 failed with error -17
>
> It seems it's a common issue if typec port supports the modal operation.
>
> ---
> drivers/usb/typec/tcpm/tcpm.c | 7 +++----
> 1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 904c7b4..59b366b 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -4594,14 +4594,13 @@ static void run_state_machine(struct tcpm_port *port)
> tcpm_set_state(port, ready_state(port), 0);
> break;
> case DR_SWAP_CHANGE_DR:
> - if (port->data_role == TYPEC_HOST) {
> - tcpm_unregister_altmodes(port);
> + tcpm_unregister_altmodes(port);
> + if (port->data_role == TYPEC_HOST)
> tcpm_set_roles(port, true, port->pwr_role,
> TYPEC_DEVICE);
> - } else {
> + else
> tcpm_set_roles(port, true, port->pwr_role,
> TYPEC_HOST);
> - }
> tcpm_ams_finish(port);
> tcpm_set_state(port, ready_state(port), 0);
> break;

Reviewed-by: Macpaul Lin <macpaul.lin@mediatek.com>

Thank for your help.

Regards,
Macpaul Lin

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