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alasdairc

Member

Registered: 2013-10-04

Posts: 16

[Solved] Qualcomm Atheros AR928X kernel oops + 'phy0: DMA fail[..snip]

Hello,
I'm having trouble with the following mini pci-express card on my Thinkpad X220.

03:00.0 Network controller: Qualcomm Atheros AR928X Wireless Network Adapter (PCI-Express) (rev 01)
	Subsystem: Fujitsu Limited. Device 147c
	Flags: bus master, fast devsel, latency 0, IRQ 17
	Memory at f2400000 (64-bit, non-prefetchable) [size=64K]
	Capabilities: <access denied>
	Kernel driver in use: ath9k
	Kernel modules: ath9k

I dual boot this laptop and the AR928X works perfectly with the same SSID when running OSX.

Dmesg output showing kernel oops on first modprobe and subsequent problems http://sprunge.us/BMaE

I need advice on how to either fix this or figure out if this is a genuine kernel bug and report it upstream.

Last edited by alasdairc (2016-07-26 23:20:29)

alasdairc

Member

Registered: 2013-10-04

Posts: 16

Re: [Solved] Qualcomm Atheros AR928X kernel oops + 'phy0: DMA fail[..snip]

I've already tried changing the nohwcrypt module paramter between enabled and disabled with no change in behaviour

alasdairc

Member

Registered: 2013-10-04

Posts: 16

Re: [Solved] Qualcomm Atheros AR928X kernel oops + 'phy0: DMA fail[..snip]

This appears to be the same issue https://bbs.archlinux.org/viewtopic.php?id=207600 from january 2016

alasdairc

Member

Registered: 2013-10-04

Posts: 16

Re: [Solved] Qualcomm Atheros AR928X kernel oops + 'phy0: DMA fail[..snip]

Given there's a kernel oops on modprobe should I just report this upstream?

alasdairc

Member

Registered: 2013-10-04

Posts: 16

Re: [Solved] Qualcomm Atheros AR928X kernel oops + 'phy0: DMA fail[..snip]

Figured this out - I should really have read the kernel oops a bit closer..

The issue is in regd.c, which I assume handles reading the regulatory domain from the eeprom. The eeprom appears to have something wrong with the country alpha2 code or regdomain hex value, and so an 'unset' state was being chosen. I think this means the frequency table didn't match my router in the UK which caused issues after a short period of time.

[    4.991229] ath: EEPROM regdomain: 0x6b
[    4.991230] ath: EEPROM indicates we should expect a direct regpair map
[    4.991232] ath: Country alpha2 being used: 00
[    4.991233] ath: Regpair used: 0x6b
[    4.991234] ------------[ cut here ]------------
[    4.991239] WARNING: CPU: 2 PID: 247 at drivers/net/wireless/ath/regd.c:244 ath_regd_init+0x13f/0x150 [ath]

Either way the driver shouldn't really bug out like this, so I will mention upstream..

Anyway, I've installed crda and set regdomain manually in

/etc/conf/wireless-regdom

and the connection is not only stronger but isn't crapping out every 20 minutes.

happy.