Re: [PATCH v3] USB: core: Disable LPM only for non-suspended ports

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Jan 02, 2025 at 02:20:13PM +0000, Jon Hunter wrote:
> Hi Greg,
> 
> On 18/12/2024 16:21, Jon Hunter wrote:
> > 
> > On 06/12/2024 07:48, Kai-Heng Feng wrote:
> > > There's USB error when tegra board is shutting down:
> > > [  180.919315] usb 2-3: Failed to set U1 timeout to 0x0,error code -113
> > > [  180.919995] usb 2-3: Failed to set U1 timeout to 0xa,error code -113
> > > [  180.920512] usb 2-3: Failed to set U2 timeout to 0x4,error code -113
> > > [  186.157172] tegra-xusb 3610000.usb: xHCI host controller not
> > > responding, assume dead
> > > [  186.157858] tegra-xusb 3610000.usb: HC died; cleaning up
> > > [  186.317280] tegra-xusb 3610000.usb: Timeout while waiting for
> > > evaluate context command
> > > 
> > > The issue is caused by disabling LPM on already suspended ports.
> > > 
> > > For USB2 LPM, the LPM is already disabled during port suspend. For USB3
> > > LPM, port won't transit to U1/U2 when it's already suspended in U3,
> > > hence disabling LPM is only needed for ports that are not suspended.
> > > 
> > > Cc: Wayne Chang <waynec@nvidia.com>
> > > Cc: stable@vger.kernel.org
> > > Fixes: d920a2ed8620 ("usb: Disable USB3 LPM at shutdown")
> > > Signed-off-by: Kai-Heng Feng <kaihengf@nvidia.com>
> > > ---
> > > v3:
> > >   Use udev->port_is_suspended which reflects upstream port status
> > > 
> > > v2:
> > >   Add "Cc: stable@vger.kernel.org"
> > > 
> > >   drivers/usb/core/port.c | 7 ++++---
> > >   1 file changed, 4 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
> > > index e7da2fca11a4..c92fb648a1c4 100644
> > > --- a/drivers/usb/core/port.c
> > > +++ b/drivers/usb/core/port.c
> > > @@ -452,10 +452,11 @@ static int usb_port_runtime_suspend(struct
> > > device *dev)
> > >   static void usb_port_shutdown(struct device *dev)
> > >   {
> > >       struct usb_port *port_dev = to_usb_port(dev);
> > > +    struct usb_device *udev = port_dev->child;
> > > -    if (port_dev->child) {
> > > -        usb_disable_usb2_hardware_lpm(port_dev->child);
> > > -        usb_unlocked_disable_lpm(port_dev->child);
> > > +    if (udev && !udev->port_is_suspended) {
> > > +        usb_disable_usb2_hardware_lpm(udev);
> > > +        usb_unlocked_disable_lpm(udev);
> > >       }
> > >   }
> > 
> > 
> > This resolves the issue I have been seeing [0].
> > 
> > Tested-by: Jon Hunter <jonathanh@nvidia.com>
> > 
> > Thanks!
> > Jon
> > 
> > [0] https://lore.kernel.org/linux-usb/
> > d5e79487-0f99-4ff2-8f49-0c403f1190af@nvidia.com/
> 
> 
> Let me know if you OK to pick up this fix now?

This is already in linux-next and in my usb-linus branch and should go
to Linus today or tomorrow.

thanks,

greg k-h