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brektrou / rtl8821CU

Realtek RTL8811CU/RTL8821CU USB Wi-Fi adapter driver for Linux
GNU General Public License v2.0
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Warm boot issue #62

Open KiraleAdmin opened 4 years ago

KiraleAdmin commented 4 years ago

I am observing a recurrent problem that I have seen before in old posts on the Internet. The issue is related to warm boot. Driver works well when I plug my USB device (rtl8821cu) in USB port when the system is turned on, also when the system does a cold boot. But if I perform a warm boot with the USB device plugged in, then the problems appear.

The result is that wireless interface is not shown in the list of available network interfaces. I have realized that issue is related to power on initialization sequence used by driver. Driver finds something different than expected and can not handle it properly.

https://pastebin.com/1qQAMWQC

KiraleAdmin commented 4 years ago

After doing more tests, I have verified that if I plug the WiFi USB device in a non-powered USB hub and this latter to the NanoPi's USB port, then it works after a warm boot.

It seems to me quite odd. Any idea?