| Message ID | 20200205112228.25155-1-kai.heng.feng@canonical.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2,1/3] xhci: Ensure link state is U3 after setting USB_SS_PORT_LS_U3 | expand |
> On Feb 5, 2020, at 19:22, Kai-Heng Feng <kai.heng.feng@canonical.com> wrote: > > The xHCI spec doesn't specify the upper bound of U3 transition time. For > some devices 20ms is not enough, so we need to make sure the link state > is in U3 before further actions. > > I've tried to use U3 Entry Capability by setting U3 Entry Enable in > config register, however the port change event for U3 transition > interrupts the system suspend process. > > For now let's use the less ideal method by polling PLS. > > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> Please ignore this series. Some patches are missing changelog, will resend one. Kai-Heng > --- > v2: > - Remove some redundant debug messages. > - Use msleep loop outside if spinlock to stop pegging CPU. > > drivers/usb/host/xhci-hub.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c > index 7a3a29e5e9d2..d3c5bcf76755 100644 > --- a/drivers/usb/host/xhci-hub.c > +++ b/drivers/usb/host/xhci-hub.c > @@ -1313,7 +1313,16 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, > xhci_set_link_state(xhci, ports[wIndex], link_state); > > spin_unlock_irqrestore(&xhci->lock, flags); > - msleep(20); /* wait device to enter */ > + if (link_state == USB_SS_PORT_LS_U3) { > + int retries = 10; > + > + while (retries--) { > + msleep(10); /* wait device to enter */ > + temp = readl(ports[wIndex]->addr); > + if ((temp & PORT_PLS_MASK) == XDEV_U3) > + break; > + } > + } > spin_lock_irqsave(&xhci->lock, flags); > > temp = readl(ports[wIndex]->addr); > -- > 2.17.1 >
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index 7a3a29e5e9d2..d3c5bcf76755 100644 --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -1313,7 +1313,16 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, xhci_set_link_state(xhci, ports[wIndex], link_state); spin_unlock_irqrestore(&xhci->lock, flags); - msleep(20); /* wait device to enter */ + if (link_state == USB_SS_PORT_LS_U3) { + int retries = 10; + + while (retries--) { + msleep(10); /* wait device to enter */ + temp = readl(ports[wIndex]->addr); + if ((temp & PORT_PLS_MASK) == XDEV_U3) + break; + } + } spin_lock_irqsave(&xhci->lock, flags); temp = readl(ports[wIndex]->addr);
The xHCI spec doesn't specify the upper bound of U3 transition time. For some devices 20ms is not enough, so we need to make sure the link state is in U3 before further actions. I've tried to use U3 Entry Capability by setting U3 Entry Enable in config register, however the port change event for U3 transition interrupts the system suspend process. For now let's use the less ideal method by polling PLS. Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> --- v2: - Remove some redundant debug messages. - Use msleep loop outside if spinlock to stop pegging CPU. drivers/usb/host/xhci-hub.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)