Re: suspend problem with dwc3 gadget / g_multi when usb disconnected

[Martin Kepplinger <martin.kepplinger@puri.sm>]

On 12.12.19 13:39, Felipe Balbi wrote:
> 
> Hi,
> 
> Martin Kepplinger <martin.kepplinger@puri.sm> writes:


>> [   64.405226] Modules linked in: rfkill st_magn_spi st_sensors_spi
>> mousedev qmi_wwan caam_jr caamhash_desc caamalg_desc cdc_wdm option
>> usbnet usb_wwan mii usbserial st_magn_i2c st_magn st_sensors_i2c
>> st_sensors industrialio_triggered_buffer goodix kfifo_buf tcpci tcpm
>> roles imx2_wdt watchdog aes_ce_blk crypto_simd typec bq25890_charger
>> caam imx_sdma virt_dma error crct10dif_ce ghash_ce sha2_ce sha1_ce
>> gpio_vibra usb_f_acm u_serial usb_f_rndis g_multi usb_f_mass_storage
>> u_ether libcomposite ip_tables x_tables ipv6 nf_defrag_ipv6
>> xhci_plat_hcd xhci_hcd usbcore dwc3 snvs_pwrkey ulpi udc_core
>> phy_fsl_imx8mq_usb usb_common
>> [   64.462126] CPU: 3 PID: 884 Comm: ip Not tainted
>> 5.5.0-rc1-next-20191212-librem5-00019-g4fb81fdd9c7d #1
>> [   64.471909] Hardware name: Purism Librem 5 devkit (DT)
>> [   64.477264] pstate: 60000085 (nZCv daIf -PAN -UAO)
>> [   64.482268] pc : dwc3_stop_active_transfer.constprop.38+0xe8/0x100 [dwc3]
>> [   64.489351] lr : dwc3_stop_active_transfer.constprop.38+0x64/0x100 [dwc3]
>> [   64.496421] sp : ffff00009f213240
>> [   64.499874] x29: ffff00009f213240 x28: 0000000000000000
>> [   64.505410] x27: ffff00009f2137b0 x26: ffff0000a4e0cc10
>> [   64.510946] x25: 0000000000000001 x24: ffff0000a324518c
>> [   64.516482] x23: ffff0000a3245193 x22: ffff0000a41f0080
>> [   64.522018] x21: 0000000000000000 x20: ffff0000a4176600
>> [   64.527553] x19: ffff800010ee87c8 x18: 0000000000000000
>> [   64.533089] x17: 0000000000000000 x16: 0000000000000000
>> [   64.538625] x15: 0000000000000000 x14: 0000000000000000
>> [   64.544160] x13: ffff0000a4176868 x12: ffff0000a4176868
>> [   64.549696] x11: ffffffffffff3f08 x10: 0000000000000008
>> [   64.555232] x9 : ffffffffffff3f04 x8 : 0000000000000811
>> [   64.560767] x7 : ffffffffffff3f00 x6 : ffffffffffff3f0c
>> [   64.566303] x5 : 0000000000000000 x4 : ffff80001007483c
>> [   64.571839] x3 : 0000000000000808 x2 : ffff00009f21327c
>> [   64.577375] x1 : 0000000000000040 x0 : 00000000ffffff92
>> [   64.582911] Call trace:
>> [   64.585474]  dwc3_stop_active_transfer.constprop.38+0xe8/0x100 [dwc3]
>> [   64.592194]  __dwc3_gadget_ep_disable+0x34/0x380 [dwc3]
>> [   64.597649]  dwc3_gadget_ep_disable+0x44/0xf8 [dwc3]
>> [   64.602841]  usb_ep_disable+0x34/0x100 [udc_core]
>> [   64.607749]  eth_stop+0xb4/0x130 [u_ether]
>> [   64.612026]  __dev_close_many+0xb4/0x138
>> [   64.616116]  __dev_change_flags+0xb8/0x1d0
>> [   64.620385]  dev_change_flags+0x28/0x68
>> [   64.624384]  do_setlink+0x30c/0xc90
>> [   64.628021]  __rtnl_newlink+0x3f8/0x788
>> [   64.632018]  rtnl_newlink+0x54/0x80
>> [   64.635654]  rtnetlink_rcv_msg+0x128/0x370
>> [   64.639926]  netlink_rcv_skb+0x60/0x120
>> [   64.643924]  rtnetlink_rcv+0x1c/0x28
>> [   64.647650]  netlink_unicast+0x1b8/0x278
>> [   64.651739]  netlink_sendmsg+0x1ac/0x3b0
>> [   64.655829]  ____sys_sendmsg+0x250/0x298
>> [   64.659918]  ___sys_sendmsg+0x88/0xc8
>> [   64.663735]  __sys_sendmsg+0x70/0xc0
>> [   64.667463]  __arm64_sys_sendmsg+0x28/0x30
>> [   64.671736]  el0_svc_common.constprop.3+0x98/0x170
>> [   64.676729]  el0_svc_handler+0x20/0x28
>> [   64.680638]  el0_sync_handler+0x134/0x1a0
>> [   64.684817]  el0_sync+0x140/0x180
>> [   64.688271] ---[ end trace 4f6aa846a9c6f20c ]---
>>
>> ... again. at every shutdown or rmmod.
>>
>> I hope that this might be already helpful.
> 
> I need to see the trace events for this failure case too. You could add
> ftrace_dump_on_oops to your cmdline and change the WARN_ONCE() to a
> BUG_ON() or something.
> 

doing that and having "ftrace=function ftrace_dump_on_oops" dumps way
too much to handle and somehow my board resets while printing...

I found I can avoid the above error during shutdown though by keeping a
few regulators enabled for now. I'm not entirely sure if that's a dwc3
problem now, so let's leave the above for now.

Back to my first issue: disconnected USB and suspend:

I disable all gadget configs now.

"echo mem > /sys/power/state" still only hangs the system - again: all
that's in the logs is:

[   97.405251] PM: suspend entry (deep)

and on the console then:

[  118.608738] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
[  118.615093] rcu: 	1-...0: (0 ticks this GP)
idle=e86/1/0x4000000000000000 softirq=16109/16109 fqs=2626
[  181.628739] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
[  181.635088] rcu: 	1-...0: (0 ticks this GP)
idle=e86/1/0x4000000000000000 softirq=16109/16109 fqs=10503
[  244.648738] rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
[  244.655087] rcu: 	1-...0: (0 ticks this GP)
idle=e86/1/0x4000000000000000 softirq=16109/16109 fqs=17402

... not sure how to further debug that.