# \[Bug 214875\] USB 3.1 device cannot be detected

- From: \<hidden\>
- Date: 2021-10-30 05:53:38 
- List: linux-usb
- Page: https://ratatoskr.run/linux-usb/2021/10/8879329
- Thread: https://ratatoskr.run/linux-usb/2021/10/8879329/t.md

```text
https://bugzilla.kernel.org/show_bug.cgi?id=214875

--- Comment #1 from Walt Jr. Brake (mr.yming81@gmail.com) ---
Yesterday I try to fix it myself, and after I revert the patch [usb: core:
reduce power-on-good delay time of root
hub](https://lore.kernel.org/all/1618017645-12259-1-git-send-email-chunfeng.yun%40mediatek.com/),
compile the kernel and test, it works.

Here is the patch:

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);
 }

 static inline int hub_port_debounce_be_connected(struct usb_hub *hub,

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