ath9k: Still seeing DMA issues in latest wireless-testing.
Looks like some potentially nice ath9k patches just got merged into wireless-testing. It has been stable and fast so far, but I do still see DMA issues in the logs.
This is on a system with 30 STAs associated with a flakey netgear running HT40-, and 30 associated with a cisco running HT20. (Through some luck, the netgear managed to send proper ht-info channel this time, so the NIC went HT40-).
ath: DMA failed to stop in 10 ms AR_CR=0x00000024 AR_DIAG_SW=0x42000020
ath: Could not stop RX, we could be confusing the DMA engine when we start RX up
ath: DMA failed to stop in 10 ms AR_CR=0x00000024 AR_DIAG_SW=0x42000020
ath: DMA failed to stop in 10 ms AR_CR=0x00000024 AR_DIAG_SW=0x42000020
ath: Could not stop RX, we could be confusing the DMA engine when we start RX up
ath: DMA failed to stop in 10 ms AR_CR=0x00000024 AR_DIAG_SW=0x42000020
sta0: authenticate with 30:46:9a:10:0b:9a (try 1)
sta0: authenticated
sta0: associate with 30:46:9a:10:0b:9a (try 1)
sta0: RX ReassocResp from 30:46:9a:10:0b:9a (capab=0x421 status=0 aid=31)
sta0: associated
ieee80211 wiphy0: Allocated STA 30:46:9a:10:0b:9a
ieee80211 wiphy0: Inserted STA 30:46:9a:10:0b:9a
ieee80211 wiphy0: WMM queue=2 aci=0 acm=0 aifs=3 cWmin=15 cWmax=1023 txop=0 uapsd=0 ieee80211 wiphy0: WMM queue=3 aci=1 acm=0 aifs=7 cWmin=15 cWmax=1023 txop=0 uapsd=0 ieee80211 wiphy0: WMM queue=1 aci=2 acm=0 aifs=2 cWmin=7 cWmax=15 txop=94 uapsd=0 ieee80211 wiphy0: WMM queue=0 aci=3 acm=0 aifs=2 cWmin=3 cWmax=7 txop=47 uapsd=0
ath: DMA failed to stop in 10 ms AR_CR=0x00000024 AR_DIAG_SW=0x42000020
ath: Could not stop RX, we could be confusing the DMA engine when we start RX up
ath: DMA failed to stop in 10 ms AR_CR=0x00000024 AR_DIAG_SW=0x42000020 ADDRCONF(NETDEV_CHANGE): sta0: link becomes ready
sta0: no IPv6 routers present
ath: DMA failed to stop in 10 ms AR_CR=0x00000024 AR_DIAG_SW=0x42000020
ath: Could not stop RX, we could be confusing the DMA engine when we start RX up
ath: DMA failed to stop in 10 ms AR_CR=0x00000024 AR_DIAG_SW=0x42000020
ath: DMA failed to stop in 10 ms AR_CR=0x00000024 AR_DIAG_SW=0x42000020
ath: Could not stop RX, we could be confusing the DMA engine when we start RX up
ath: DMA failed to stop in 10 ms AR_CR=0x00000024 AR_DIAG_SW=0x42000020
ath: DMA failed to stop in 10 ms AR_CR=0x00000024 AR_DIAG_SW=0x42000020
ath: Could not stop RX, we could be confusing the DMA engine when we start RX up
ath: DMA failed to stop in 10 ms AR_CR=0x00000024 AR_DIAG_SW=0x42000020
Thanks,
Ben
Signature · 2 lines
Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com
Quoted 8 lines · Ben Greear
Looks like some potentially nice ath9k patches just got merged into wireless-testing. It has been stable and fast so far, but I do still see DMA issues in the logs.
This is on a system with 30 STAs associated with a flakey netgear running HT40-, and 30 associated with a cisco running HT20. (Through some luck, the netgear managed to send proper ht-info channel this time, so the NIC went HT40-).
Ben, the fact that you see much more of these DMA issues when you're running your virtual STAs suggests to me that root cause is some race condition between dma and cpu. The main difference between the 60 STA use-case and the one STA use case is that rx irq processing will take longer with multiple STAs, right? Is there some other difference?
/Björn
Quoted 10 lines · Björn Smedman
Quoted 8 lines · Ben Greear
Looks like some potentially nice ath9k patches just got merged into wireless-testing. It has been stable and fast so far, but I do still see DMA issues in the logs.
This is on a system with 30 STAs associated with a flakey netgear running HT40-, and 30 associated with a cisco running HT20. (Through some luck, the netgear managed to send proper ht-info channel this time, so the NIC went HT40-).
Quoted 5 lines
Ben, the fact that you see much more of these DMA issues when you're running your virtual STAs suggests to me that root cause is some race condition between dma and cpu. The main difference between the 60 STA use-case and the one STA use case is that rx irq processing will take longer with multiple STAs, right? Is there some other difference?
I don't know. I see it even when not running much traffic.
I also see DMA on my AP system, which has a single AP and one idle station. Granted, I have 128 or so stations connected to the AP, but again, the stations are mostly idle.
Other folks see the DMA issues too...and most probably just don't report them anymore...
Thanks,
Ben
Quoted 2 lines
/Björn
Signature · 2 lines
Ben Greear <[email protected]> Candela Technologies Inc http://www.candelatech.com