Re: [PATCH v10 0/6] Re-introduce TX FIFO resize for larger EP bursting

From: Ferry Toth
Date: Mon Aug 23 2021 - 14:55:01 EST

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Op 23-08-2021 om 17:34 schreef Pavel Hofman:

Dne 23. 08. 21 v 17:21 Andy Shevchenko napsal(a):

On Mon, Aug 23, 2021 at 5:59 PM Pavel Hofman <pavel.hofman@xxxxxxxxxxx> wrote:
Dne 22. 08. 21 v 21:43 Ferry Toth napsal(a):

Op 19-08-2021 om 23:04 schreef Pavel Hofman:

Dne 19. 08. 21 v 22:10 Ferry Toth napsal(a):

Op 19-08-2021 om 09:51 schreef Pavel Hofman:

Dne 18. 08. 21 v 21:07 Ferry Toth napsal(a):

Op 18-08-2021 om 00:00 schreef Ferry Toth:

...

So, where do we go from here?

I know the patches have been tested on dwc2 (by me and others). I
do not know if Ruslan or Jerome tested them on dwc3 but probably
not. Ruslan has talked about RPi (my case too) and BeagleboneBlack,
both with dwc2. Perhaps the dwc2 behaves a bit differently than dwc3?

The patches add a new EP-IN for async feedback. I am sorry I have
not followed your long thread (it started as unrelated to uac). Does
the problem appear with f_uac1 or f_uac2? Please how have you
reached the above problem?

I'm sorry too. I first believed the issue was related to the patch
mentioned in the subject line.

The problem appaers with f_uac2. I bost Edison_Arduino board in host
mode (there is a switch allowing to select host/device mode). When
flipping the switch to device mode udev run a script:
But as I am using configfs (excerpt follows) and just disabling the
last 2 line resolves the issue, I'm guessing uac2 is the issue. Or
exceeding the available resources.

# Create directory structure
mkdir "${GADGET_BASE_DIR}"
cd "${GADGET_BASE_DIR}"
mkdir -p configs/c.1/strings/0x409
mkdir -p strings/0x409

# Serial device
mkdir functions/gser.usb0
ln -s functions/gser.usb0 configs/c.1/
###

# Ethernet device
mkdir functions/eem.usb0
echo "${DEV_ETH_ADDR}" > functions/eem.usb0/dev_addr
echo "${HOST_ETH_ADDR}" > functions/eem.usb0/host_addr
ln -s functions/eem.usb0 configs/c.1/

# Mass Storage device
mkdir functions/mass_storage.usb0
echo 1 > functions/mass_storage.usb0/stall
echo 0 > functions/mass_storage.usb0/lun.0/cdrom
echo 0 > functions/mass_storage.usb0/lun.0/ro
echo 0 > functions/mass_storage.usb0/lun.0/nofua
echo "${USBDISK}" > functions/mass_storage.usb0/lun.0/file
ln -s functions/mass_storage.usb0 configs/c.1/

# UAC2 device
mkdir functions/uac2.usb0
ln -s functions/uac2.usb0 configs/c.1
....

As you say, could perhaps the reason be that the extra EP-IN added in
those patches (previously 1, now 2 with the default config you use)
exceeds your EP-IN max count or available fifos somehow? You have a
number of functions initialized. If you change the load order of the
functions, do you get the error later with a different function? Just
guessing...

You should be able to switch the default async EP-OUT (which
configures the new feedback EP-IN ) to adaptive EP-OUT (which requires
no feedback EP) with c_sync=8 parameter of f_uac2.

https://elixir.bootlin.com/linux/v5.14-rc6/source/drivers/usb/gadget/function/f_uac2.c#L47

https://elixir.bootlin.com/linux/v5.14-rc6/source/drivers/usb/gadget/function/f_uac2.c#L830

https://elixir.bootlin.com/linux/v5.14-rc6/source/include/uapi/linux/usb/ch9.h#L453

Does that fix the problem?

Not sure how to do that. Do you mean the module should have a parameter
called c_sync? `modinfo` list no parameters for usb_f_uac2.

Those are configfs params, not available in modinfo.

I checked and the value is "adaptive"
https://elixir.bootlin.com/linux/v5.14-rc7/source/drivers/usb/gadget/function/f_uac2.c#L1312

In your configfs script:

Kernel shouldn't crash with any available set of configuration
parameters, right? So, even if the parameter would fix the crash the
series is buggy and has to be reverted in my opinion.

I will send in reverts tomorrow, unless someone has a better idea.

Sure, no problem with reverting. I am just trying to start up some troubleshooting. A resource exhaustion was mentioned here, that's why I suggested a way to test the patch with the original number of endpoints allocated. I do not get any crashes on my setup which uses fewer gadget functions. That's why I asked what happens if the functions load order is changed. I am afraid this thread is so complex that the actual problem has been burried in the history.

I found some time to test your suggestions. So below 3 cases on rc6 with the reverts removed again:
1) the original configfs setup script
2) with uac2 moved to the top so it is created first (I hope)
3) same as 1) but with c_sync = adaptive

Summary:
1) still shows the crash as expected
2) has no effect
3) resolves the issue as you expect

1) Normal configfs order (uac2 last)
------------------------------------

root@yuna:~# [ 50.975986] BUG: kernel NULL pointer dereference, address: 0000000000000008
[ 50.983125] #PF: supervisor write access in kernel mode
[ 50.988470] #PF: error_code(0x0002) - not-present page
[ 50.993723] PGD 0 P4D 0
[ 50.996327] Oops: 0002 [#1] SMP PTI
[ 50.999899] CPU: 0 PID: 596 Comm: irq/14-dwc3 Tainted: G W 5.14.0-rc6-edison-acpi-standard #1
[ 51.009948] Hardware name: Intel Corporation Merrifield/BODEGA BAY, BIOS 542 2015.01.21:18.19.48
[ 51.018922] RIP: 0010:dwc3_gadget_del_and_unmap_request+0x19/0xe0
[ 51.025169] Code: 8b 78 08 e8 89 d6 ff ff 48 89 ef 5d e9 f0 61 a6 ff 41 54 55 48 89 f5 53 48 8b 46 68 48 89 fb 48 8b 4e 60 4c 8b a7 90 00 00 00 <48> 89 41 08 48 89 08 48 b8 00 01 00 00
00 00 ad de 80 a6 b4 00 00
[ 51.044345] RSP: 0000:ffffb2ea40313c10 EFLAGS: 00010093
[ 51.049692] RAX: ffff94dc03aa2c48 RBX: ffff94dc03aa2c00 RCX: 0000000000000000
[ 51.056985] RDX: 00000000ffffff94 RSI: ffff94dc02303d80 RDI: ffff94dc03aa2c00
[ 51.064278] RBP: ffff94dc02303d80 R08: 0000000000000014 R09: 0000000000000001
[ 51.071572] R10: ffff94dc02303d80 R11: 0000000000000001 R12: ffff94dc08b43028
[ 51.078864] R13: ffff94dc03aa2c48 R14: 0000000000000000 R15: ffff94dc031b3c00
[ 51.086159] FS: 0000000000000000(0000) GS:ffff94dc3e200000(0000) knlGS:0000000000000000
[ 51.094429] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 51.100304] CR2: 0000000000000008 CR3: 0000000007e20000 CR4: 00000000001006f0
[ 51.107596] Call Trace:
[ 51.110103] dwc3_remove_requests.constprop.0+0x12f/0x170
[ 51.115637] __dwc3_gadget_ep_disable+0x7a/0x160
[ 51.120366] dwc3_gadget_ep_disable+0x3d/0xd0
[ 51.124827] usb_ep_disable+0x1c/0x70
[ 51.128586] u_audio_stop_capture+0x79/0x120 [u_audio]
[ 51.133857] afunc_set_alt+0x73/0x80 [usb_f_uac2]
[ 51.138683] composite_setup+0x224/0x1b90 [libcomposite]
[ 51.144137] ? __dwc3_gadget_kick_transfer+0x160/0x400
[ 51.149404] ? configfs_composite_setup+0x6b/0x90 [libcomposite]
[ 51.155562] configfs_composite_setup+0x6b/0x90 [libcomposite]
[ 51.161544] dwc3_ep0_interrupt+0x466/0xa70
[ 51.165831] dwc3_thread_interrupt+0x829/0xe90
[ 51.170379] ? __schedule+0x235/0x6c0
[ 51.174138] ? disable_irq_nosync+0x10/0x10
[ 51.178425] irq_thread_fn+0x1b/0x60
[ 51.182092] irq_thread+0xc0/0x160
[ 51.185580] ? irq_thread_check_affinity+0x70/0x70
[ 51.190486] ? irq_forced_thread_fn+0x70/0x70
[ 51.194948] kthread+0x122/0x140
[ 51.198259] ? set_kthread_struct+0x40/0x40
[ 51.202545] ret_from_fork+0x22/0x30
[ 51.206214] Modules linked in: usb_f_uac2 u_audio usb_f_mass_storage usb_f_eem u_ether usb_f_serial u_serial libcomposite rfcomm iptable_nat bnep spi_pxa2xx_platform snd_sof_nocodec dw_dmac smsc smsc95xx intel_mrfld_pwrbtn intel_mrfld_adc dw_dmac_pci pwm_lpss_pci dw_dmac_core pwm_lpss snd_sof_pci_intel_tng snd_sof_pci snd_sof_intel_ipc snd_sof_intel_atom snd_sof snd_sof_xtensa_dsp snd_soc_acpi spi_pxa2xx_pci brcmfmac brcmutil hci_uart btbcm ti_ads7950 industrialio_triggered_buffer kfifo_buf leds_gpio ledtrig_timer ledtrig_heartbeat mmc_block extcon_intel_mrfld sdhci_pci cqhci sdhci led_class mmc_core intel_soc_pmic_mrfld btrfs libcrc32c xor zstd_compress zlib_deflate raid6_pq
[ 51.267592] CR2: 0000000000000008
[ 51.270981] ---[ end trace 135abe76b19414cc ]---

ferry@delfion:~$ cat /proc/asound/Gadget/stream0
USBArmory USBArmory Gadget at usb-0000:00:14.0-5, high speed : USB Audio

Playback:
Status: Stop
Interface 4
Altset 1
Format: S16_LE
Channels: 2
Endpoint: 0x04 (4 OUT) (ASYNC)
Rates: 64000
Data packet interval: 1000 us
Bits: 16
Channel map: FL FR
Sync Endpoint: 0x85 (5 IN)
Sync EP Interface: 4
Sync EP Altset: 1
Implicit Feedback Mode: No

Capture:
Status: Stop
Interface 5
Altset 1
Format: S16_LE
Channels: 2
Endpoint: 0x86 (6 IN) (ASYNC)
Rates: 48000
Data packet interval: 1000 us
Bits: 16
Channel map: FL FR

root@delfion:~# lsusb -v -d 1d6b:0104 | grep EP.*IN
bEndpointAddress 0x82 EP 2 IN
bEndpointAddress 0x83 EP 3 IN
bEndpointAddress 0x84 EP 4 IN
bEndpointAddress 0x85 EP 5 IN
bEndpointAddress 0x86 EP 6 IN
can't get debug descriptor: Resource temporarily unavailable
cannot read device status, Resource temporarily unavailable (11)

2) uac2 first in configfs
-------------------------

root@yuna:~# [ 172.094997] BUG: kernel NULL pointer dereference, address: 0000000000000008
[ 172.102136] #PF: supervisor write access in kernel mode
[ 172.107480] #PF: error_code(0x0002) - not-present page
[ 172.112733] PGD 0 P4D 0
[ 172.115338] Oops: 0002 [#1] SMP PTI
[ 172.118909] CPU: 0 PID: 604 Comm: irq/14-dwc3 Tainted: G W 5.14.0-rc6-edison-acpi-standard #1
[ 172.128958] Hardware name: Intel Corporation Merrifield/BODEGA BAY, BIOS 542 2015.01.21:18.19.48
[ 172.137931] RIP: 0010:dwc3_gadget_del_and_unmap_request+0x19/0xe0
[ 172.144175] Code: 8b 78 08 e8 89 d6 ff ff 48 89 ef 5d e9 f0 61 a6 ff 41 54 55 48 89 f5 53 48 8b 46 68 48 89 fb 48 8b 4e 60 4c 8b a7 90 00 00 00 <48> 89 41 08 48 89 08 48 b8 00 01 00 00
00 00 ad de 80 a6 b4 00 00
[ 172.163352] RSP: 0018:ffffa1438053bc10 EFLAGS: 00010097
[ 172.168698] RAX: ffff9b76c7ec3848 RBX: ffff9b76c7ec3800 RCX: 0000000000000000
[ 172.175990] RDX: 00000000ffffff94 RSI: ffff9b76c79ffc00 RDI: ffff9b76c7ec3800
[ 172.183283] RBP: ffff9b76c79ffc00 R08: 0000000000000014 R09: 0000000000000001
[ 172.190577] R10: ffff9b76c79ffc00 R11: 0000000000000002 R12: ffff9b76c8a66028
[ 172.197870] R13: ffff9b76c7ec3848 R14: 0000000000000000 R15: ffff9b76c7255c00
[ 172.205163] FS: 0000000000000000(0000) GS:ffff9b76fe200000(0000) knlGS:0000000000000000
[ 172.213436] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 172.219309] CR2: 0000000000000008 CR3: 000000001360c000 CR4: 00000000001006f0
[ 172.226600] Call Trace:
[ 172.229107] dwc3_remove_requests.constprop.0+0x12f/0x170
[ 172.234640] __dwc3_gadget_ep_disable+0x7a/0x160
[ 172.239372] dwc3_gadget_ep_disable+0x3d/0xd0
[ 172.243834] usb_ep_disable+0x1c/0x70
[ 172.247590] u_audio_stop_capture+0x79/0x120 [u_audio]
[ 172.252862] afunc_set_alt+0x73/0x80 [usb_f_uac2]
[ 172.257688] composite_setup+0x224/0x1b90 [libcomposite]
[ 172.263143] ? __dwc3_gadget_kick_transfer+0x160/0x400
[ 172.268410] ? configfs_composite_setup+0x6b/0x90 [libcomposite]
[ 172.274568] configfs_composite_setup+0x6b/0x90 [libcomposite]
[ 172.280551] dwc3_ep0_interrupt+0x466/0xa70
[ 172.284834] ? newidle_balance.constprop.0+0xfa/0x380
[ 172.290008] dwc3_thread_interrupt+0x829/0xe90
[ 172.294561] ? __schedule+0x235/0x6c0
[ 172.298316] ? disable_irq_nosync+0x10/0x10
[ 172.302606] irq_thread_fn+0x1b/0x60
[ 172.306272] irq_thread+0xc0/0x160
[ 172.309761] ? irq_thread_check_affinity+0x70/0x70
[ 172.314666] ? irq_forced_thread_fn+0x70/0x70
[ 172.319128] kthread+0x122/0x140
[ 172.322440] ? set_kthread_struct+0x40/0x40
[ 172.326724] ret_from_fork+0x22/0x30
[ 172.330390] Modules linked in: usb_f_mass_storage usb_f_eem u_ether usb_f_serial u_serial usb_f_uac2 u_audio libcomposite rfcomm iptable_nat bnep snd_sof_nocodec spi_pxa2xx_platform dw_dmac smsc smsc95xx pwm_lpss_pci pwm_lpss snd_sof_pci_intel_tng snd_sof_pci snd_sof_intel_ipc intel_mrfld_pwrbtn snd_sof_intel_atom intel_mrfld_adc dw_dmac_pci dw_dmac_core snd_sof snd_sof_xtensa_dsp snd_soc_acpi spi_pxa2xx_pci brcmfmac brcmutil hci_uart leds_gpio btbcm ti_ads7950 industrialio_triggered_buffer kfifo_buf ledtrig_timer ledtrig_heartbeat mmc_block extcon_intel_mrfld sdhci_pci cqhci sdhci led_class mmc_core intel_soc_pmic_mrfld btrfs libcrc32c xor zstd_compress zlib_deflate raid6_pq
[ 172.391766] CR2: 0000000000000008
[ 172.395157] ---[ end trace 8272319264d5a2c0 ]---

3) With c_sync = adaptive
-------------------------
# UAC2 device
mkdir functions/uac2.usb0
echo "adaptive" > functions/uac2.usb0/c_sync
ln -s functions/uac2.usb0 configs/c.1

(No BUG)

root@delfion:~# cat /proc/asound/Gadget/stream0
USBArmory USBArmory Gadget at usb-0000:00:14.0-5, high speed : USB Audio

Playback:
Status: Stop
Interface 4
Altset 1
Format: S16_LE
Channels: 2
Endpoint: 0x04 (4 OUT) (ADAPTIVE)
Rates: 64000
Data packet interval: 1000 us
Bits: 16
Channel map: FL FR

Capture:
Status: Stop
Interface 5
Altset 1
Format: S16_LE
Channels: 2
Endpoint: 0x85 (5 IN) (ASYNC)
Rates: 48000
Data packet interval: 1000 us
Bits: 16
Channel map: FL FR

root@delfion:~# lsusb -v -d 1d6b:0104 | grep EP.*IN
bEndpointAddress 0x82 EP 2 IN
bEndpointAddress 0x83 EP 3 IN
bEndpointAddress 0x84 EP 4 IN
bEndpointAddress 0x85 EP 5 IN
can't get debug descriptor: Resource temporarily unavailable

Again, I am not the author of the patches, my USB knowledge is way unsufficient for that. I am trying to make them work as they are important and make the existing audio gadget actually usable.

Thanks for the suggestions, I didn't think to set params through configfs.

Maybe this will help in tracing the root cause, although that's way over my head.

Thanks,

Pavel.

Next message: Brijesh Singh: "Re: [PATCH Part1 v5 11/38] x86/compressed: Add helper for validating pages in the decompression stage"
Previous message: Dmitry Osipenko: "Re: [PATCH v8 07/34] clk: tegra: Support runtime PM and power domain"
In reply to: Pavel Hofman: "Re: [PATCH v10 0/6] Re-introduce TX FIFO resize for larger EP bursting"
Next in thread: Thinh Nguyen: "Re: [PATCH v10 0/6] Re-introduce TX FIFO resize for larger EP bursting"
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