> -----Original Message-----
> From: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>
> Sent: Thursday, July 23, 2020 4:36 AM
> To: Jun Li <jun.li@xxxxxxx>; balbi@xxxxxxxxxx
> Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] usb: dwc3: debugfs: do not queue work if try to change mode
> on non-drd
>
> Hi,
>
> Li Jun wrote:
> > Do not try to queue a drd work for change mode if the port is not a
> > drd, this is to avoid below kernel dump:
>
> Are you talking about OTG or DRD? This patch seems to be for OTG. If you need to
> debug and manually do role switch for DRD from userspace, enable and use role class
> sysfs attribute.
There is no problem in normal cases, I triggered this warning
when try to change the role for a single role port via this debugfs
file, I think nothing should stop user to use this file for debug
purpose.
There is condition check of USB_DR_MODE_OTG when init drd_work, but
no this check when queue work, so maybe a better change is to move
the condition check from __dwc3_set_mode() into dwc3_set_mode()
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 6adaa7d..2fa50ec 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -120,9 +120,6 @@ static void __dwc3_set_mode(struct work_struct *work)
unsigned long flags;
int ret;
- if (dwc->dr_mode != USB_DR_MODE_OTG)
- return;
-
pm_runtime_get_sync(dwc->dev);
if (dwc->current_dr_role == DWC3_GCTL_PRTCAP_OTG)
@@ -205,6 +202,9 @@ void dwc3_set_mode(struct dwc3 *dwc, u32 mode)
{
unsigned long flags;
+ if (dwc->dr_mode != USB_DR_MODE_OTG)
+ return;
+
spin_lock_irqsave(&dwc->lock, flags);
dwc->desired_dr_role = mode;
spin_unlock_irqrestore(&dwc->lock, flags);
Thanks
Li Jun
>
> BR,
> Thinh
>
> > [ 60.115529] ------------[ cut here ]------------
> > [ 60.120166] WARNING: CPU: 1 PID: 627 at kernel/workqueue.c:1473
> > __queue_work+0x46c/0x520
> > [ 60.128254] Modules linked in:
> > [ 60.131313] CPU: 1 PID: 627 Comm: sh Not tainted
> > 5.7.0-rc4-00022-g914a586-dirty #135
> > [ 60.139054] Hardware name: NXP i.MX8MQ EVK (DT)
> > [ 60.143585] pstate: a0000085 (NzCv daIf -PAN -UAO)
> > [ 60.148376] pc : __queue_work+0x46c/0x520
> > [ 60.152385] lr : __queue_work+0x314/0x520
> > [ 60.156393] sp : ffff8000124ebc40
> > [ 60.159705] x29: ffff8000124ebc40 x28: ffff800011808018
> > [ 60.165018] x27: ffff800011819ef8 x26: ffff800011d39980
> > [ 60.170331] x25: ffff800011808018 x24: 0000000000000100
> > [ 60.175643] x23: 0000000000000013 x22: 0000000000000001
> > [ 60.180955] x21: ffff0000b7c08e00 x20: ffff0000b6c31080
> > [ 60.186267] x19: ffff0000bb99bc00 x18: 0000000000000000
> > [ 60.191579] x17: 0000000000000000 x16: 0000000000000000
> > [ 60.196891] x15: 0000000000000000 x14: 0000000000000000
> > [ 60.202202] x13: 0000000000000000 x12: 0000000000000000
> > [ 60.207515] x11: 0000000000000000 x10: 0000000000000040
> > [ 60.212827] x9 : ffff800011d55460 x8 : ffff800011d55458
> > [ 60.218138] x7 : ffff0000b7800028 x6 : 0000000000000000
> > [ 60.223450] x5 : ffff0000b7800000 x4 : 0000000000000000
> > [ 60.228762] x3 : ffff0000bb997cc0 x2 : 0000000000000001
> > [ 60.234074] x1 : 0000000000000000 x0 : ffff0000b6c31088
> > [ 60.239386] Call trace:
> > [ 60.241834] __queue_work+0x46c/0x520
> > [ 60.245496] queue_work_on+0x6c/0x90
> > [ 60.249075] dwc3_set_mode+0x48/0x58
> > [ 60.252651] dwc3_mode_write+0xf8/0x150
> > [ 60.256489] full_proxy_write+0x5c/0xa8
> > [ 60.260327] __vfs_write+0x18/0x40
> > [ 60.263729] vfs_write+0xdc/0x1c8
> > [ 60.267045] ksys_write+0x68/0xf0
> > [ 60.270360] __arm64_sys_write+0x18/0x20
> > [ 60.274286] el0_svc_common.constprop.0+0x68/0x160
> > [ 60.279077] do_el0_svc+0x20/0x80
> > [ 60.282394] el0_sync_handler+0x10c/0x178
> > [ 60.286403] el0_sync+0x140/0x180
> > [ 60.289716] ---[ end trace 70b155582e2b7988 ]---
> >
> > Signed-off-by: Li Jun <jun.li@xxxxxxx>
> > ---
> > drivers/usb/dwc3/debugfs.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/usb/dwc3/debugfs.c b/drivers/usb/dwc3/debugfs.c
> > index 6d9de33..99e7f53 100644
> > --- a/drivers/usb/dwc3/debugfs.c
> > +++ b/drivers/usb/dwc3/debugfs.c
> > @@ -428,6 +428,9 @@ static ssize_t dwc3_mode_write(struct file *file,
> > if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
> > return -EFAULT;
> >
> > + if (dwc->dr_mode != USB_DR_MODE_OTG)
> > + return count;
> > +
> > if (!strncmp(buf, "host", 4))
> > mode = DWC3_GCTL_PRTCAP_HOST;
> >
