When a new USB device gets plugged to nested hubs, the affected hub,
which connects to usb 2-1.4-port2, doesn't report there's any change,
hence the nested hubs go back to runtime suspend like nothing happened:
[ 281.032951] usb usb2: usb wakeup-resume
[ 281.032959] usb usb2: usb auto-resume
[ 281.032974] hub 2-0:1.0: hub_resume
[ 281.033011] usb usb2-port1: status 0263 change 0000
[ 281.033077] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
[ 281.049797] usb 2-1: usb wakeup-resume
[ 281.069800] usb 2-1: Waited 0ms for CONNECT
[ 281.069810] usb 2-1: finish resume
[ 281.070026] hub 2-1:1.0: hub_resume
[ 281.070250] usb 2-1-port4: status 0203 change 0000
[ 281.070272] usb usb2-port1: resume, status 0
[ 281.070282] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
[ 281.089813] usb 2-1.4: usb wakeup-resume
[ 281.109792] usb 2-1.4: Waited 0ms for CONNECT
[ 281.109801] usb 2-1.4: finish resume
[ 281.109991] hub 2-1.4:1.0: hub_resume
[ 281.110147] usb 2-1.4-port2: status 0263 change 0000
[ 281.110234] usb 2-1-port4: resume, status 0
[ 281.110239] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
[ 281.110266] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
[ 281.110426] hub 2-1.4:1.0: hub_suspend
[ 281.110565] usb 2-1.4: usb auto-suspend, wakeup 1
[ 281.130998] hub 2-1:1.0: hub_suspend
[ 281.137788] usb 2-1: usb auto-suspend, wakeup 1
[ 281.142935] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
[ 281.177828] usb 2-1: usb wakeup-resume
[ 281.197839] usb 2-1: Waited 0ms for CONNECT
[ 281.197850] usb 2-1: finish resume
[ 281.197984] hub 2-1:1.0: hub_resume
[ 281.198203] usb 2-1-port4: status 0203 change 0000
[ 281.198228] usb usb2-port1: resume, status 0
[ 281.198237] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
[ 281.217835] usb 2-1.4: usb wakeup-resume
[ 281.237834] usb 2-1.4: Waited 0ms for CONNECT
[ 281.237845] usb 2-1.4: finish resume
[ 281.237990] hub 2-1.4:1.0: hub_resume
[ 281.238067] usb 2-1.4-port2: status 0263 change 0000
[ 281.238148] usb 2-1-port4: resume, status 0
[ 281.238152] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
[ 281.238166] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
[ 281.238385] hub 2-1.4:1.0: hub_suspend
[ 281.238523] usb 2-1.4: usb auto-suspend, wakeup 1
[ 281.258076] hub 2-1:1.0: hub_suspend
[ 281.265744] usb 2-1: usb auto-suspend, wakeup 1
[ 281.285976] hub 2-0:1.0: hub_suspend
[ 281.285988] usb usb2: bus auto-suspend, wakeup 1
USB 3.2 spec, 9.2.5.4 "Changing Function Suspend State" says that "If
the link is in a non-U0 state, then the device must transition the link
to U0 prior to sending the remote wake message", but the hub only
transits the link to U0 after signaling remote wakeup.
So be more forgiving and use a 20ms delay to let the link transit to U0
for remote wakeup.
Suggested-by: Alan Stern <[email protected]>
Signed-off-by: Kai-Heng Feng <[email protected]>
---
v2:
- Add a small delay instead of waking up all hubs.
drivers/usb/core/hub.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 00070a8a65079..576fdf2c9f3c8 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1110,7 +1110,10 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
} else {
hub_power_on(hub, true);
}
- }
+ /* Give some time on remote wakeup to let links to transit to U0 */
+ } else if (hub_is_superspeed(hub->hdev))
+ msleep(20);
+
init2:
/*
--
2.33.1
On Wed, Dec 15, 2021 at 08:01:06PM +0800, Kai-Heng Feng wrote:
> When a new USB device gets plugged to nested hubs, the affected hub,
> which connects to usb 2-1.4-port2, doesn't report there's any change,
> hence the nested hubs go back to runtime suspend like nothing happened:
> [ 281.032951] usb usb2: usb wakeup-resume
> [ 281.032959] usb usb2: usb auto-resume
> [ 281.032974] hub 2-0:1.0: hub_resume
> [ 281.033011] usb usb2-port1: status 0263 change 0000
> [ 281.033077] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
> [ 281.049797] usb 2-1: usb wakeup-resume
> [ 281.069800] usb 2-1: Waited 0ms for CONNECT
> [ 281.069810] usb 2-1: finish resume
> [ 281.070026] hub 2-1:1.0: hub_resume
> [ 281.070250] usb 2-1-port4: status 0203 change 0000
> [ 281.070272] usb usb2-port1: resume, status 0
> [ 281.070282] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
> [ 281.089813] usb 2-1.4: usb wakeup-resume
> [ 281.109792] usb 2-1.4: Waited 0ms for CONNECT
> [ 281.109801] usb 2-1.4: finish resume
> [ 281.109991] hub 2-1.4:1.0: hub_resume
> [ 281.110147] usb 2-1.4-port2: status 0263 change 0000
> [ 281.110234] usb 2-1-port4: resume, status 0
> [ 281.110239] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
> [ 281.110266] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
> [ 281.110426] hub 2-1.4:1.0: hub_suspend
> [ 281.110565] usb 2-1.4: usb auto-suspend, wakeup 1
> [ 281.130998] hub 2-1:1.0: hub_suspend
> [ 281.137788] usb 2-1: usb auto-suspend, wakeup 1
> [ 281.142935] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
> [ 281.177828] usb 2-1: usb wakeup-resume
> [ 281.197839] usb 2-1: Waited 0ms for CONNECT
> [ 281.197850] usb 2-1: finish resume
> [ 281.197984] hub 2-1:1.0: hub_resume
> [ 281.198203] usb 2-1-port4: status 0203 change 0000
> [ 281.198228] usb usb2-port1: resume, status 0
> [ 281.198237] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
> [ 281.217835] usb 2-1.4: usb wakeup-resume
> [ 281.237834] usb 2-1.4: Waited 0ms for CONNECT
> [ 281.237845] usb 2-1.4: finish resume
> [ 281.237990] hub 2-1.4:1.0: hub_resume
> [ 281.238067] usb 2-1.4-port2: status 0263 change 0000
> [ 281.238148] usb 2-1-port4: resume, status 0
> [ 281.238152] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
> [ 281.238166] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
> [ 281.238385] hub 2-1.4:1.0: hub_suspend
> [ 281.238523] usb 2-1.4: usb auto-suspend, wakeup 1
> [ 281.258076] hub 2-1:1.0: hub_suspend
> [ 281.265744] usb 2-1: usb auto-suspend, wakeup 1
> [ 281.285976] hub 2-0:1.0: hub_suspend
> [ 281.285988] usb usb2: bus auto-suspend, wakeup 1
>
> USB 3.2 spec, 9.2.5.4 "Changing Function Suspend State" says that "If
> the link is in a non-U0 state, then the device must transition the link
> to U0 prior to sending the remote wake message", but the hub only
> transits the link to U0 after signaling remote wakeup.
>
> So be more forgiving and use a 20ms delay to let the link transit to U0
> for remote wakeup.
>
> Suggested-by: Alan Stern <[email protected]>
> Signed-off-by: Kai-Heng Feng <[email protected]>
> ---
> v2:
> - Add a small delay instead of waking up all hubs.
>
> drivers/usb/core/hub.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 00070a8a65079..576fdf2c9f3c8 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -1110,7 +1110,10 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
> } else {
> hub_power_on(hub, true);
> }
> - }
> + /* Give some time on remote wakeup to let links to transit to U0 */
> + } else if (hub_is_superspeed(hub->hdev))
> + msleep(20);
Where did the 20-ms number come from? Is it mentioned in the spec as
the time required for a port to switch from U3 to U0?
Alan Stern
On Wed, Dec 15, 2021 at 11:47 PM Alan Stern <[email protected]> wrote:
>
> On Wed, Dec 15, 2021 at 08:01:06PM +0800, Kai-Heng Feng wrote:
> > When a new USB device gets plugged to nested hubs, the affected hub,
> > which connects to usb 2-1.4-port2, doesn't report there's any change,
> > hence the nested hubs go back to runtime suspend like nothing happened:
> > [ 281.032951] usb usb2: usb wakeup-resume
> > [ 281.032959] usb usb2: usb auto-resume
> > [ 281.032974] hub 2-0:1.0: hub_resume
> > [ 281.033011] usb usb2-port1: status 0263 change 0000
> > [ 281.033077] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
> > [ 281.049797] usb 2-1: usb wakeup-resume
> > [ 281.069800] usb 2-1: Waited 0ms for CONNECT
> > [ 281.069810] usb 2-1: finish resume
> > [ 281.070026] hub 2-1:1.0: hub_resume
> > [ 281.070250] usb 2-1-port4: status 0203 change 0000
> > [ 281.070272] usb usb2-port1: resume, status 0
> > [ 281.070282] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
> > [ 281.089813] usb 2-1.4: usb wakeup-resume
> > [ 281.109792] usb 2-1.4: Waited 0ms for CONNECT
> > [ 281.109801] usb 2-1.4: finish resume
> > [ 281.109991] hub 2-1.4:1.0: hub_resume
> > [ 281.110147] usb 2-1.4-port2: status 0263 change 0000
> > [ 281.110234] usb 2-1-port4: resume, status 0
> > [ 281.110239] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
> > [ 281.110266] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
> > [ 281.110426] hub 2-1.4:1.0: hub_suspend
> > [ 281.110565] usb 2-1.4: usb auto-suspend, wakeup 1
> > [ 281.130998] hub 2-1:1.0: hub_suspend
> > [ 281.137788] usb 2-1: usb auto-suspend, wakeup 1
> > [ 281.142935] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
> > [ 281.177828] usb 2-1: usb wakeup-resume
> > [ 281.197839] usb 2-1: Waited 0ms for CONNECT
> > [ 281.197850] usb 2-1: finish resume
> > [ 281.197984] hub 2-1:1.0: hub_resume
> > [ 281.198203] usb 2-1-port4: status 0203 change 0000
> > [ 281.198228] usb usb2-port1: resume, status 0
> > [ 281.198237] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
> > [ 281.217835] usb 2-1.4: usb wakeup-resume
> > [ 281.237834] usb 2-1.4: Waited 0ms for CONNECT
> > [ 281.237845] usb 2-1.4: finish resume
> > [ 281.237990] hub 2-1.4:1.0: hub_resume
> > [ 281.238067] usb 2-1.4-port2: status 0263 change 0000
> > [ 281.238148] usb 2-1-port4: resume, status 0
> > [ 281.238152] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
> > [ 281.238166] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
> > [ 281.238385] hub 2-1.4:1.0: hub_suspend
> > [ 281.238523] usb 2-1.4: usb auto-suspend, wakeup 1
> > [ 281.258076] hub 2-1:1.0: hub_suspend
> > [ 281.265744] usb 2-1: usb auto-suspend, wakeup 1
> > [ 281.285976] hub 2-0:1.0: hub_suspend
> > [ 281.285988] usb usb2: bus auto-suspend, wakeup 1
> >
> > USB 3.2 spec, 9.2.5.4 "Changing Function Suspend State" says that "If
> > the link is in a non-U0 state, then the device must transition the link
> > to U0 prior to sending the remote wake message", but the hub only
> > transits the link to U0 after signaling remote wakeup.
> >
> > So be more forgiving and use a 20ms delay to let the link transit to U0
> > for remote wakeup.
> >
> > Suggested-by: Alan Stern <[email protected]>
> > Signed-off-by: Kai-Heng Feng <[email protected]>
> > ---
> > v2:
> > - Add a small delay instead of waking up all hubs.
> >
> > drivers/usb/core/hub.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> > index 00070a8a65079..576fdf2c9f3c8 100644
> > --- a/drivers/usb/core/hub.c
> > +++ b/drivers/usb/core/hub.c
> > @@ -1110,7 +1110,10 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
> > } else {
> > hub_power_on(hub, true);
> > }
> > - }
> > + /* Give some time on remote wakeup to let links to transit to U0 */
> > + } else if (hub_is_superspeed(hub->hdev))
> > + msleep(20);
>
> Where did the 20-ms number come from? Is it mentioned in the spec as
> the time required for a port to switch from U3 to U0?
The 20ms is the minimal time the device take to bring link back to U0 reliably.
The spec mentioned device has to transit the link to U0 before
signaling remote wakeup.
So do you think this requires a new quirk?
Kai-Heng
>
> Alan Stern
On Thu, Dec 16, 2021 at 08:23:29AM +0800, Kai-Heng Feng wrote:
> On Wed, Dec 15, 2021 at 11:47 PM Alan Stern <[email protected]> wrote:
> >
> > On Wed, Dec 15, 2021 at 08:01:06PM +0800, Kai-Heng Feng wrote:
> > > --- a/drivers/usb/core/hub.c
> > > +++ b/drivers/usb/core/hub.c
> > > @@ -1110,7 +1110,10 @@ static void hub_activate(struct usb_hub *hub, enum hub_activation_type type)
> > > } else {
> > > hub_power_on(hub, true);
> > > }
> > > - }
> > > + /* Give some time on remote wakeup to let links to transit to U0 */
> > > + } else if (hub_is_superspeed(hub->hdev))
> > > + msleep(20);
> >
> > Where did the 20-ms number come from? Is it mentioned in the spec as
> > the time required for a port to switch from U3 to U0?
>
> The 20ms is the minimal time the device take to bring link back to U0 reliably.
> The spec mentioned device has to transit the link to U0 before
> signaling remote wakeup.
> So do you think this requires a new quirk?
No, I just wondered where you got the number from. The patch looks fine; I
can't think of any reasonable way to improve it.
Acked-by: Alan Stern <[email protected]>
Alan Stern
On Wed, 2021-12-15 at 20:01 +0800, Kai-Heng Feng wrote:
> When a new USB device gets plugged to nested hubs, the affected hub,
> which connects to usb 2-1.4-port2, doesn't report there's any change,
> hence the nested hubs go back to runtime suspend like nothing
> happened:
> [ 281.032951] usb usb2: usb wakeup-resume
> [ 281.032959] usb usb2: usb auto-resume
> [ 281.032974] hub 2-0:1.0: hub_resume
> [ 281.033011] usb usb2-port1: status 0263 change 0000
> [ 281.033077] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
> [ 281.049797] usb 2-1: usb wakeup-resume
> [ 281.069800] usb 2-1: Waited 0ms for CONNECT
> [ 281.069810] usb 2-1: finish resume
> [ 281.070026] hub 2-1:1.0: hub_resume
> [ 281.070250] usb 2-1-port4: status 0203 change 0000
> [ 281.070272] usb usb2-port1: resume, status 0
> [ 281.070282] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
> [ 281.089813] usb 2-1.4: usb wakeup-resume
> [ 281.109792] usb 2-1.4: Waited 0ms for CONNECT
> [ 281.109801] usb 2-1.4: finish resume
> [ 281.109991] hub 2-1.4:1.0: hub_resume
> [ 281.110147] usb 2-1.4-port2: status 0263 change 0000
> [ 281.110234] usb 2-1-port4: resume, status 0
> [ 281.110239] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
> [ 281.110266] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
> [ 281.110426] hub 2-1.4:1.0: hub_suspend
> [ 281.110565] usb 2-1.4: usb auto-suspend, wakeup 1
> [ 281.130998] hub 2-1:1.0: hub_suspend
> [ 281.137788] usb 2-1: usb auto-suspend, wakeup 1
> [ 281.142935] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
> [ 281.177828] usb 2-1: usb wakeup-resume
> [ 281.197839] usb 2-1: Waited 0ms for CONNECT
> [ 281.197850] usb 2-1: finish resume
> [ 281.197984] hub 2-1:1.0: hub_resume
> [ 281.198203] usb 2-1-port4: status 0203 change 0000
> [ 281.198228] usb usb2-port1: resume, status 0
> [ 281.198237] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
> [ 281.217835] usb 2-1.4: usb wakeup-resume
> [ 281.237834] usb 2-1.4: Waited 0ms for CONNECT
> [ 281.237845] usb 2-1.4: finish resume
> [ 281.237990] hub 2-1.4:1.0: hub_resume
> [ 281.238067] usb 2-1.4-port2: status 0263 change 0000
> [ 281.238148] usb 2-1-port4: resume, status 0
> [ 281.238152] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
> [ 281.238166] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
> [ 281.238385] hub 2-1.4:1.0: hub_suspend
> [ 281.238523] usb 2-1.4: usb auto-suspend, wakeup 1
> [ 281.258076] hub 2-1:1.0: hub_suspend
> [ 281.265744] usb 2-1: usb auto-suspend, wakeup 1
> [ 281.285976] hub 2-0:1.0: hub_suspend
> [ 281.285988] usb usb2: bus auto-suspend, wakeup 1
>
> USB 3.2 spec, 9.2.5.4 "Changing Function Suspend State" says that "If
> the link is in a non-U0 state, then the device must transition the
> link
> to U0 prior to sending the remote wake message", but the hub only
> transits the link to U0 after signaling remote wakeup.
>
> So be more forgiving and use a 20ms delay to let the link transit to
> U0
> for remote wakeup.
>
> Suggested-by: Alan Stern <[email protected]>
> Signed-off-by: Kai-Heng Feng <[email protected]>
> ---
> v2:
> - Add a small delay instead of waking up all hubs.
>
> drivers/usb/core/hub.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 00070a8a65079..576fdf2c9f3c8 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -1110,7 +1110,10 @@ static void hub_activate(struct usb_hub *hub,
> enum hub_activation_type type)
> } else {
> hub_power_on(hub, true);
> }
> - }
> + /* Give some time on remote wakeup to let links to transit to
> U0 */
> + } else if (hub_is_superspeed(hub->hdev))
> + msleep(20);
add {}?
> +
> init2:
>
> /*