On Wed, Nov 03, 2021 at 10:37:33PM +0200, Mathias Nyman wrote: > On 2.11.2021 22.29, Walt Jr. Brake wrote: > > On 2/11/2021 17:05, Mathias Nyman wrote: > >> On 1.11.2021 16.06, Alan Stern wrote: > >>> On Sat, Oct 30, 2021 at 12:49:37PM +0800, Walt Jr. Brake wrote: > >>>> This patch make USB 3.1 device cannot be detected, and I report the bug [1] > >>>> to archlinux three month ago. Yesterday I try to fix it myself, and after I > >>>> revert this patch, compile the kernel and test, it works. > >>>> > >>>> [1] https://bugs.archlinux.org/task/71660?project=1&pagenum=2 > >>>> > >>>> > >>>> diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h > >>>> index 22ea1f4f2d66..73f4482d833a 100644 > >>>> --- a/drivers/usb/core/hub.h > >>>> +++ b/drivers/usb/core/hub.h > >>>> @@ -148,10 +148,8 @@ static inline unsigned hub_power_on_good_delay(struct > >>>> usb_hub *hub) > >>>> { > >>>> unsigned delay = hub->descriptor->bPwrOn2PwrGood * 2; > >>>> > >>>> - if (!hub->hdev->parent) /* root hub */ > >>>> - return delay; > >>>> - else /* Wait at least 100 msec for power to become stable */ > >>>> - return max(delay, 100U); > >>>> + /* Wait at least 100 msec for power to become stable */ > >>>> + return max(delay, 100U); > >>>> } > >>> Mathias: > >>> > >>> It looks like the bPwrOn2PwrGood value in xhci-hcd's hub descriptor is > >>> too small for some USB 3.1 devices. > >>> > >>> Can you look into this? > >>> > >>> Alan Stern > >>> > >> At first glance the xhci roothub bPwrOn2PwrGood value looks ok. > >> xhci spec 5.4.8 states software should wait 20ms after asserting PP, before > >> attempting to change the state of the port. > >> > >> xhci driver sets desc->bPwrOn2PwrGood = 10; (2ms interval, so equals 20ms ) > >> > >> We should probably get this working immediately, so maybe revert that patch > >> while looking into the rootcause. > >> > >> Walt Jr. Brake, instead of reverting that patch, could you test if changing the > >> xhci roothub bPwrOn2PwrGood value helps. > >> > >> diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c > >> index a3f875eea751..756231a55602 100644 > >> --- a/drivers/usb/host/xhci-hub.c > >> +++ b/drivers/usb/host/xhci-hub.c > >> @@ -257,7 +257,7 @@ static void xhci_common_hub_descriptor(struct xhci_hcd *xhci, > >> { > >> u16 temp; > >> - desc->bPwrOn2PwrGood = 10; /* xhci section 5.4.9 says 20ms max */ > >> + desc->bPwrOn2PwrGood = 50; /* The 20ms in xhci 5.4.8 isn't enough for USB 3.1 */ > >> desc->bHubContrCurrent = 0; > >> desc->bNbrPorts = ports; > >> > >> Thanks > >> -Mathias > > > > Mathias: > > > > Sorry to reply lately. I test with your patch, it works. > > > > I also test with setting bPwrOn2PwrGood to 45, and it not work. > > > > Seems that the minimal value should be 50 for this case. > > > > Thanks for testing, and for checking that 90ms wait isn't enough Can you send a "real" patch for this so I can get it into the tree soon to resolve the regression? thanks, greg k-h
