Re: 4.10.9 nok with realtek wlan, atom

From: Larry Finger
Date: Sun Apr 16 2017 - 15:31:00 EST


On 04/16/2017 01:09 PM, rupert THURNER wrote:
On Sun, Apr 16, 2017 at 6:02 PM, Larry Finger <Larry.Finger@xxxxxxxxxxxx> wrote:
On 04/16/2017 05:23 AM, rupert THURNER wrote:

On Sat, Apr 15, 2017 at 10:40 PM, Larry Finger
<Larry.Finger@xxxxxxxxxxxx> wrote:

On 04/14/2017 03:26 PM, rupert THURNER wrote:


On Thu, Feb 9, 2017 at 9:09 PM, Larry Finger <Larry.Finger@xxxxxxxxxxxx>
wrote:


On 02/09/2017 01:43 PM, Bjorn Helgaas wrote:



[+cc rtl8192ce folks in case they've seen this]

On Thu, Feb 09, 2017 at 03:45:01PM +0100, rupert THURNER wrote:



hi,

not technical expert enough, i just wanted to give a short user
feedback. for realtek wlan on atom, kernels up to 4.9.5 are ok, and
kernel 4.10.0-rc7-g926af6273fc6 (arch linux-git version numbering) as
well. kernels 4.9.6, 4.9.7, and 4.9.8 fail, i.e. connection to a WLAN
hotspot is possible then drops, or connecting to wlan fails
alltogether.




Thanks very much for your report, and sorry for the inconvenience.

v4.10-rc7 works, so I guess we don't need to worry about fixing v4.10.

But the stable kernels v4.9.6, v4.9.7, and v4.9.8 are broken, so we
need to figure out why and make sure we fix the v4.9 stable series.

I can't tell yet whether this is PCI-related or not. If it is,
4922a6a5cfa7 ("PCI: Enumerate switches below PCI-to-PCIe bridges")
appeared in v4.9.6, and there is a known issue with that. The issue
should be fixed by 610c2b7ff8f6 ("PCI/ASPM: Handle PCI-to-PCIe bridges
as roots of PCIe hierarchies"), which appeared in v4.9.9, so I guess
the first thing to do would be to test v4.9.9.

If it's not fixed in v4.9.9, can you share the complete dmesg log
(output of "dmesg" command) and "lspci -vv" output for v4.9.5 (last
known working version) and v4.9.6 (first known broken version)? On
v4.9.6, collect the dmesg output after the failure occurs.

24: PCI 300.0: 0282 WLAN controller
[Created at pci.366]
Model: "Realtek RTL8188CE 802.11b/g/n WiFi Adapter"
Device: pci 0x8176 "RTL8188CE 802.11b/g/n WiFi Adapter"
Revision: 0x01
Driver: "rtl8192ce"
Driver Modules: "rtl8192ce"
Device File: wlp3s0
Features: WLAN




It would be helpful if someone were to bisect this issue. The only
issue
that comes to mind was fixed in commit 52f5631a4c05 ("rtlwifi:
rtl8192ce:
Fix loading of incorrect firmware") which is in 4.10-rc7 and will be
backported to 4.9.

The above issue is one that could not be reproduced on my hardware,
thus
it
took Jurij Smakov to find the fix. Without his bisection of the
problem,
who
knows how long it would have taken to find my edit mistake.



larry, using the newest kernel 4.10.8 the network connection dropps
again irregular.

# dmesg
[ 0.000000] Linux version 4.10.9-1-ARCH (builduser@tobias) (gcc
version 6.3.1 20170306 (GCC) ) #1 SMP PREEMPT Sat Apr 8 12:39:59 CEST
2017
[ 11.933373] rtl8192ce: rtl8192ce: Power Save off (module option)
[ 11.933396] rtl8192ce: Using firmware rtlwifi/rtl8192cfw.bin
[ 11.978307] ieee80211 phy0: Selected rate control algorithm 'rtl_rc'
[ 11.978945] rtlwifi: rtlwifi: wireless switch is on

# lspci -vv
Subsystem: Realtek Semiconductor Co., Ltd. RTL8188CE 802.11b/g/n WiFi
Adapter
Kernel driver in use: rtl8192ce



Is firmware rtlwifi/rtl8192cfw.bin also used on kernels that work?


4.10.x used to work. 4.10.6 or 4.10.7 it started failing? i am not too
sure about it.

# ls -l /usr/lib/firmware/rtlwifi/rtl8192cfw.bin
-rw-r--r-- 1 root root 16192 Mar 10 12:15
/usr/lib/firmware/rtlwifi/rtl8192cfw.bin


That does not answer my question.
4.10, 4.10.2, 4.10.3, 4.10.5 worked. as far as i can tell
rtl8192cfw.bin did not change and was used. with kernels 4.9 there was
a phase where rtl8192cfwU.bin was loaded which did not work. or i do
not understand your question correctly?

I think you mean that rtl8192cfw.bin was the firmware used for both a good and a bad kernel.

My problem is that there are at least 6 varieties of chips that use the rtl8192ce driver. I do not have all of them, but so far it is impossible for me to tell if yours is the same as one of mine. If you post the output of 'lspci -nn', then I might be able to answer that question.

A second problem is that there are no fixes in any 4.10.x kernel where x >= 1 that can cause a problem in rtl8192ce, thus it is hard to know how 4.10.5 can work and 4.10.6 or 7 can fail! That is the reason that a bisection would be useful.

At this point, and with the information you have provided, I'm not sure if the problem is even in rtl8192ce, or how I can help.

Larry