Re: [Bug ?] 10ec:b723 Realtek RTL8723BE wireless card drops connection

Re: [Bug ?] 10ec:b723 Realtek RTL8723BE wireless card drops connection

[Larry Finger]

On 06/14/2015 02:56 AM, Arnaud LE CAM wrote:
> Larry and Jes,
>
> The problem is that wifi connection drops randomly (reconnecting each 600 sec.) when flwps option is set to 1.
> Many tests have been done on this bug, including with 4.1.0-040100rc7 kernel :
> - flwps=0 and ips=0 works fine ;
> - flwps=1 and ips=0 (equals to ips=0 with no other options) works fine only with 802.11g under 4.1.0-040100rc7 ;
> - flwps=0 and ips=1 works fine ;
> - flwps=1 and ips=1 results in a bug.
> This bug was triaged by Christopher M. Penalver on Ubuntu's Launchpad (https://bugs.launchpad.net/bugs/1459367) where all tests are attached.
>
> I hope it could help...

Never, ever, ever drop the Cc to the mailing list. By doing that, you are 
requesting private consultation, but without any offer to pay for such personal 
service. That is rude. In fact, I usually ignore such postings.

On the other hand, this description of the problem is nearly perfect. The reader 
does not have to look at pages of information that is likely not significant.

To address your problem, power saving does not work correctly on this device. 
That is why there are numerous posts on the web telling people to use ips=0. It 
seems that Ubuntu people never look at anything but the Ubuntu literature; 
however, I'm sure that I posted this "suggestion" there as well. The Realtek 
group is currently rewriting the entire dynamic management code for all their 
drivers. When complete, this should improve performance and should help the 
power-save condition. No, I do not know when the new code will be ready, or how 
much improvement it will make.

Larry

Re: [Bug ?] 10ec:b723 Realtek RTL8723BE wireless card drops connection

[James Cameron]

On Sun, Jun 14, 2015 at 10:10:30AM -0500, Larry Finger wrote:
> To address your problem, power saving does not work correctly on
> this device. That is why there are numerous posts on the web telling
> people to use ips=0. It seems that Ubuntu people never look at
> anything but the Ubuntu literature; however, I'm sure that I posted
> this "suggestion" there as well. The Realtek group is currently
> rewriting the entire dynamic management code for all their drivers.
> When complete, this should improve performance and should help the
> power-save condition. No, I do not know when the new code will be
> ready, or how much improvement it will make.

Thanks for summary.

OLPC is also seeing the issue.  Power saving mode impacts battery run
time; one of our design goals.  ips=0 seems to solve with 3.19, but
not fully with 4.1-rc7; still some periods of packet loss.

I offer to test any rtl8723be changes.

(I'm also looking into IBSS, because Sugar desktop relies on
ad-hoc.  No beacons on creating an IBSS through NetworkManager, but
beacons are fine with "iw dev wlan0 ibss join x 2437".  But I'm not
yet ready to report problem; still some debugging to do.)

-- 
James Cameron
http://quozl.linux.org.au/

Re: [Bug ?] 10ec:b723 Realtek RTL8723BE wireless card drops connection

[Larry Finger]

On 06/14/2015 06:04 PM, James Cameron wrote:
> On Sun, Jun 14, 2015 at 10:10:30AM -0500, Larry Finger wrote:
>> To address your problem, power saving does not work correctly on
>> this device. That is why there are numerous posts on the web telling
>> people to use ips=0. It seems that Ubuntu people never look at
>> anything but the Ubuntu literature; however, I'm sure that I posted
>> this "suggestion" there as well. The Realtek group is currently
>> rewriting the entire dynamic management code for all their drivers.
>> When complete, this should improve performance and should help the
>> power-save condition. No, I do not know when the new code will be
>> ready, or how much improvement it will make.
>
> Thanks for summary.
>
> OLPC is also seeing the issue.  Power saving mode impacts battery run
> time; one of our design goals.  ips=0 seems to solve with 3.19, but
> not fully with 4.1-rc7; still some periods of packet loss.
>
> I offer to test any rtl8723be changes.

Please do a bisection between 4.1-rc7 and 3.19.

Larry

Re: [Bug ?] 10ec:b723 Realtek RTL8723BE wireless card drops connection

[James Cameron]

On Sun, Jun 14, 2015 at 06:13:56PM -0500, Larry Finger wrote:
> On 06/14/2015 06:04 PM, James Cameron wrote:
> >On Sun, Jun 14, 2015 at 10:10:30AM -0500, Larry Finger wrote:
> >>To address your problem, power saving does not work correctly on
> >>this device. That is why there are numerous posts on the web telling
> >>people to use ips=0. It seems that Ubuntu people never look at
> >>anything but the Ubuntu literature; however, I'm sure that I posted
> >>this "suggestion" there as well. The Realtek group is currently
> >>rewriting the entire dynamic management code for all their drivers.
> >>When complete, this should improve performance and should help the
> >>power-save condition. No, I do not know when the new code will be
> >>ready, or how much improvement it will make.
> >
> >Thanks for summary.
> >
> >OLPC is also seeing the issue.  Power saving mode impacts battery run
> >time; one of our design goals.  ips=0 seems to solve with 3.19, but
> >not fully with 4.1-rc7; still some periods of packet loss.
> >
> >I offer to test any rtl8723be changes.
> 
> Please do a bisection between 4.1-rc7 and 3.19.

Thanks.  But I was too hasty in reporting a good result.

Now no difference across those kernel versions; still some
periods of packet loss with ips=0.

Workaround is to use both ips=0 and fwlps=0.  We'll ship with that
unless we hear of a fix.

-- 
James Cameron
http://quozl.linux.org.au/