Re: dire state of rtl driver in 3.7

From: Larry Finger
Date: Sun Dec 23 2012 - 14:10:40 EST


On 12/22/2012 11:49 PM, Mike Galbraith wrote:
On Sun, 2012-12-23 at 00:09 +0900, Norbert Preining wrote:

Network card is built in into a Lenovo Thinkpad Edge

Toshiba Satellite.
# lspci -nnv -s 03:00.0
03:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8191SEvB
Wireless LAN Controller [10ec:8172] (rev 10)
Subsystem: Realtek Semiconductor Co., Ltd. Device [10ec:e020]

[10ec:8181] here.

Effects:
- either does not associate at all with the AP
- or the kernel believes it is associated and packages ping to the router
get stuck for up to 50+ seconds!!!
- the kernel believes everything is fine but actually nothing gets out
(Destination unreachable)
- wild ping time up-down:
64 bytes from 192.168.0.1: icmp_req=73 ttl=255 time=3.05 ms
64 bytes from 192.168.0.1: icmp_req=74 ttl=255 time=6.42 ms
64 bytes from 192.168.0.1: icmp_req=75 ttl=255 time=1.21 ms
64 bytes from 192.168.0.1: icmp_req=76 ttl=255 time=6808 ms
64 bytes from 192.168.0.1: icmp_req=77 ttl=255 time=5800 ms
64 bytes from 192.168.0.1: icmp_req=78 ttl=255 time=4792 ms

...

Looks a lot like my driver experience with older kernels, I had to use
the external driver in the rare event that I needed wireless to work.
The in tree driver works peachy these days (needed it recently, was
pleasantly surprised when it _just worked_, not even a hiccup), so
somebody cared, gave at least the 10ec:8181 bits some serious love.

Note, the RTL8188CE uses rtl8192ce, while the RTL8191SE uses rtl8192se. They share the underlying plumbing in driver rtlwifi, but the rest is completely different.

The reason that rtl8192ce now works with your device is that the so-called B-Cut chip was not supported until recently. The fix required 2 patches. The first was simple enough to be backported to stable; however the second was too invasive for that. Accordingly the second part had to wait for kernel 3.7.

Larry


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