Bug 97101

Summary:	Intel Centrino Advanced-N 6205 [Taylor Peak] with 11n_disabled=0 conflicts with BCM2045B (BDC-2.1)
Product:	Drivers	Reporter:	Jonas Thiem (jonasthiem)
Component:	Bluetooth	Assignee:	drivers_network-wireless (drivers_network-wireless)
Status:	REOPENED ---
Severity:	normal	CC:	linville
Priority:	P1
Hardware:	x86-64
OS:	Linux
Kernel Version:	3.19.3	Subsystem:
Regression:	No	Bisected commit-id:

Description Jonas Thiem 2015-04-22 21:55:02 UTC

In the default configuration by Fedora 21, I experience close to 100% packet loss when trying to use my wifi with Intel Centrino Advanced-N 6205 [Taylor Peak] while using bluetooth 4.0 audio while at the same time. Also, the bluetooth connection times out really often.

However, if I load iwlwifi with 11n_disabled=1, I don't even get any noticeable slow down or bluetooth drop outs.

Therefore, either this conflict should be fixed (I suppose it's some sort of driver bug since both bluetooth and wifi use that chip at the same time I guess?) or bluetooth activation should auto-disable the n-standard of the wifi for this particular chip.

I'm not entirely sure the bluetooth actually uses this chip as well, if not this bug report is probably wrong. This is my lspci output:

jonas@cyberman#8: lspci
00:00.0 Host bridge: Intel Corporation 2nd Generation Core Processor Family DRAM Controller (rev 09)
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
00:16.0 Communication controller: Intel Corporation 6 Series/C200 Series Chipset Family MEI Controller #1 (rev 04)
00:19.0 Ethernet controller: Intel Corporation 82579LM Gigabit Network Connection (rev 04)
00:1a.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 1 (rev b4)
00:1c.1 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 2 (rev b4)
00:1c.3 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 4 (rev b4)
00:1c.4 PCI bridge: Intel Corporation 6 Series/C200 Series Chipset Family PCI Express Root Port 5 (rev b4)
00:1d.0 USB controller: Intel Corporation 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation QM67 Express Chipset Family LPC Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller (rev 04)
00:1f.3 SMBus: Intel Corporation 6 Series/C200 Series Chipset Family SMBus Controller (rev 04)
03:00.0 Network controller: Intel Corporation Centrino Advanced-N 6205 [Taylor Peak] (rev 34)
0d:00.0 System peripheral: Ricoh Co Ltd PCIe SDXC/MMC Host Controller (rev 07)
jonas@cyberman#8:

Comment 1 Emmanuel Grumbach 2015-04-23 13:14:59 UTC

This chip doesn't support Bluetooth.

Comment 2 Jonas Thiem 2015-04-23 13:15:17 UTC

Ok, the bluetooth device is this one apparently: Broadcom Corp. BCM2045B (BDC-2.1)

It's connected through the usb hub internally which is why it's not listed on lspci but only lsusb.

Nevertheless, the intel wifi chip's n-standard results in great conflicts with the bluetooth when enabled. Maybe the broadcom chip still transmits through the intel one? (I heard that is sometimes the case in modern laptops, bt and wifi using the same chip to transmit)

Anyway, you'll probably know a lot better what the potential problem is here. I can only tell disabling n wifi helps, and therefore maybe that should be done automatically.

Comment 3 Emmanuel Grumbach 2015-04-23 13:20:12 UTC

There is no communication between the 2 chips. Nothing can be done here.

Comment 4 Jonas Thiem 2015-04-23 13:25:48 UTC

There is an obvious problem: wifi stops working when bluetooth is enabled when those two chips are combined in a laptop.

There is at least one possible obvious solution: auto-disable the n-standard through the kernel driver as soon as bluetooth is used.

And you say nothing can be done? Are you saying implementing such behavior in the kernel would be impossible? That seems very unlikely. (disclaimer: I'm not a kernel developer myself.)

Comment 5 Jonas Thiem 2015-04-23 13:36:18 UTC

Reopening with a better title that involves both chips, because the issue still appears to be real, no matter how not nice the first proposal of a fix might be.

Unless this is limited to my machine of course - I'd be happy to see other people reporting who have a similar machine... I have a Thinkpad X220 here with the listed intel centrino wifi and broadcom bluetooth chip.

Comment 6 Emmanuel Grumbach 2015-04-23 13:46:02 UTC

Intel can't do much here. Removing Intel. You can ask for support from Broadcom. Good luck.

Comment 7 Jonas Thiem 2015-04-23 14:13:34 UTC

Due to Emmanuel's suggestion that this should maybe be fixed on the Broadcom/Bluetooth side of things, changing component to "Bluetooth".

Problem in a nutshell:

* iwlwifi 11n_disabled=0 with Centrino Advanced-N 6205 gets greatly shaken by BCM2045B A2DP audio connections (wifi almost stops working entirely, it's like a 56kbps modem)

* iwlwifi 11n_disabled=1 with Centrino Advanced-N 6205 coexists nicely with the bluetooth, however, that is not the default.

Comment 8 Jonas Thiem 2016-05-23 10:15:15 UTC

Well I no longer have the specific hardware in question...

This component does have a kernel maintainer though, right?