Bug 1294298 - Impossible to set the bit rate of the WLAN interface
Summary: Impossible to set the bit rate of the WLAN interface
Keywords:
Status: CLOSED EOL
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 22
Hardware: x86_64
OS: Linux
unspecified
medium
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2015-12-26 16:35 UTC by Janusz
Modified: 2016-07-19 20:00 UTC (History)
9 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2016-07-19 20:00:06 UTC
Type: Bug


Attachments (Terms of Use)

Description Janusz 2015-12-26 16:35:36 UTC
Description of problem:

It is impossible to set the bit rate of the wireless interface manually. 
E.g., the command:  
#iwconfig wlp2s0 rate 1M
does not change the bit rate to 1 Mbit/s. 

Version-Release number of selected component (if applicable):
Fedora 22, kernel 4.2.8-200.fc22.x86_64. (also, Fedora 22 or 23 from Live USB)

Output of rpm -q linux-firmware iwl3160-firmware:
linux-firmware-20151030-58.git66d3d8d7.fc22.noarch
iwl3160-firmware-25.30.13.0-58.fc22.noarch

How reproducible:
Boot Fedora 22 and try to change the bit rate. 

Steps to Reproduce:
1. Boot Fedora 22
2. Check the current bit rate: #iwconfig wlp2s0
3. Now try to change it to a different value: #iwconfig wlp2s0 rate 1M
4. Check the bit rate again. It does not change. 

Actual results:
The bit rate does not change.

Expected results:
The bit rate should change.

Additional info:

Changing the bit rate manually is very useful in a multipath environment (e.g., the router downstairs or in a different room), since the automatic procedure often fails to set it optimally. In some situations it is even impossible to connect to the router at all at the rate set automatically.  

Toshiba Z30-B-119 laptop. Intel i5-5200U CPU. Fedora 22 64 bit. 
Network controller: Intel Corporation Wireless 3160 (rev cb)

Comment 1 John W. Linville 2016-01-04 15:42:13 UTC
iwconfig is long deprecated.  You will need to use iw instead.

https://wireless.wiki.kernel.org/en/users/Documentation/iw#modifying_transmit_bitrates

Comment 2 Janusz 2016-01-13 09:48:06 UTC
Hi! Thank you for the answer. I finally tested it fully and unfortunately it only seems to work, but it does not. 

Testing procedure

I set 1 Mbit/s mode:  # iw dev wlp2s0 set bitrates legacy-2.4 1
I test it with the command #iw dev wlp2s0 link 
The output of this command shows that the mode was changed to 1 Mbit/s. 
However, to make sure it works, and explain why I still have trouble connecting to the AP, I used a spectrum analyzer, and found out from the spectrum that an OFDM mode is used, that is 6 Mbit/s or more, instead of DSSS mode in 1 Mbit/s.

Comment 3 Emmanuel Grumbach 2016-01-13 19:20:55 UTC
I am not sure we really fully support this command. I'd have to check.
Please understand that this type of bug has a low priority.

Comment 4 Emmanuel Grumbach 2016-01-23 21:21:06 UTC
I looked at the code, iwlwifi doesn't seem to be checking for rates that may have been masked with this command.
We will probably not fix it though:

"Setting preference for transmitting using MCS rates is supported by letting you specify the band and MCS rate. Note that whether or not the device actually listens to your petition will vary depending on the device driver and cooperation from the firmware."

Comment 5 Fedora End Of Life 2016-07-19 20:00:06 UTC
Fedora 22 changed to end-of-life (EOL) status on 2016-07-19. Fedora 22 is
no longer maintained, which means that it will not receive any further
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of
Fedora please feel free to reopen this bug against that version. If you
are unable to reopen this bug, please file a new report against the
current release. If you experience problems, please add a comment to this
bug.

Thank you for reporting this bug and we are sorry it could not be fixed.


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