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 -Mathias
