From: Jes Sorensen <jes.sorensen@gmail.com>
Subject: Re: Slow connection with rtl8xxxu and 8192eu chipset
To: Nikolay Borisov <n.borisov.lkml@gmail.com>,
        linux-wireless@vger.kernel.org
References: <1195e649-c57f-1247-a0dc-2f0cc0732a00@gmail.com>
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 <61e93af9-ef8a-5319-5a23-0b622d3cf0d0@gmail.com>
 <7cb804e5-c1f5-a5d4-764d-e5a786625093@gmail.com>
Message-ID: <0b5d91b2-7e79-5767-aab7-7911806454a3@gmail.com> (sfid-20171128_173531_474945_B73A08C6)
Date: Tue, 28 Nov 2017 11:35:24 -0500
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On 11/28/2017 11:26 AM, Nikolay Borisov wrote:
> 
> 
> On 28.11.2017 18:16, Jes Sorensen wrote:
>> On 11/14/2017 05:39 AM, Nikolay Borisov wrote:
>>>
>>>
>>> On 14.11.2017 11:26, Nikolay Borisov wrote:
>>>> (Please CC as I'm not subscribed)
>>>>
>>>> Hello,
>>>>
>>>> I have the tp-link tl-wn822N usb wifi dongle. lsbusb reports it as
>>>>
>>>> Bus 001 Device 003: ID 2357:0108
>>>>
>>>> Unfortunately with the in-kernel rtl8xxxu driver I don't get very good
>>>> results:
>>>>
>>>> wifi1     IEEE 802.11  ESSID:"HOME"
>>>>           Mode:Managed  Frequency:2.462 GHz  Access Point:
>>>> 30:B5:C2:75:A4:CD
>>>>           Bit Rate=1 Mb/s   Tx-Power=20 dBm
>>>>           Retry short limit:7   RTS thr=2347 B   Fragment thr:off
>>>>           Power Management:off
>>>>           Link Quality=26/70  Signal level=-84 dBm
>>>>           Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
>>>>           Tx excessive retries:0  Invalid misc:165   Missed beacon:0
>>>>
>>>>
>>>> At the same time if I use an out of tree driver acquired from github:
>>>> https://github.com/Mange/rtl8192eu-linux-driver I get the following:
>>>>
>>>> wifi1     IEEE 802.11bgn  ESSID:"HOME"  Nickname:"<WIFI@REALTEK>"
>>>>           Mode:Managed  Frequency:2.462 GHz  Access Point:
>>>> 30:B5:C2:75:A4:CD
>>>>           Bit Rate:144.4 Mb/s   Sensitivity:0/0
>>>>           Retry:off   RTS thr:off   Fragment thr:off
>>>>           Power Management:off
>>>>           Link Quality=81/100  Signal level=100/100  Noise level=0/100
>>>>           Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
>>>>           Tx excessive retries:0  Invalid misc:0   Missed beacon:0
>>>>
>>>> Clearly this is a software problem of the in-kernel driver. I'm using
>>>> v4.10.17 with commit c14239f23adb ("rtl8xxxu: Add another 8192eu device
>>>> to the USB list") so that my device is recognised. Latest commit for
>>>> that driver in my kernel is: c59f13bbead4 ("rtl8xxxu: Work around issue
>>>> with 8192eu and 8723bu devices not reconnecting").
>>>>
>>>> Any ideas what I can do to further debug this, I'd really like to use
>>>> the in-kernel driver ?
>>>
>>> I just tested with verbatim 4.14 and even though the wireless works, 
>>> iwconfig reports something strange: 
>>>
>>> iwconfig wifi1
>>> wifi1     no wireless extensions.
>>>
>>> However, my device works as expected (albeit still slow): 
>>>
>>> wifi1     Link encap:Ethernet  HWaddr 18:d6:c7:0d:47:3c  
>>>           inet addr:10.20.1.175  Bcast:10.20.1.255  Mask:255.255.255.0
>>>           inet6 addr: fe80::281d:5f27:eb1b:8ded/64 Scope:Link
>>>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>>>           RX packets:38903 errors:0 dropped:0 overruns:0 frame:0
>>>           TX packets:24689 errors:0 dropped:0 overruns:0 carrier:0
>>>           collisions:0 txqueuelen:1000 
>>>           RX bytes:51524413 (51.5 MB)  TX bytes:5503039 (5.5 MB)
>>
>> iwconfig has been deprecated for a decade, but maybe you could elaborate
>> on what you feel is strange in this output?
> 
> Well there are 2 things:
> 
> 1. The low bitrate - which I've confirmed doing actual data test, ie,
> not just the number but the fact that the speeds are low.
> 
> 2. The worse signal level/link quality.

I don't see either of those in the iwconfig output

The low TX bitrate is a known issue. Somehow the firmware rate handling
doesn't seem to work (or it works differently than I assumed) similar to
for the 8188eu. It's something I need to figure out when I have some time.

As for link quality is this something you measured or read out of 'iw' ?

Thanks,
Jes