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ath9k bugs and known issues
This page documents all known bugs for ath9k and issues. If you are on an old kernel or an old stable kernel you will want to read this. We try to keep this page updated as we merge important pages into Linux.
- ath9k bugs and known issues
- Reported bugs on ath9k
- Most common known issues
- FreeBSD Atheros ath driver bugs
Reported bugs on ath9k
This is a collection of bug reports both unresolved and resolved to help users track issues and to find patches for fixes which have not yet been merged.
All reported ath9k bugs
All currently open ath9k bugs
This is the list of all currently open filed bugs on kernel.org.
Issues being looked into
These issue are currently being looked into. None.
Issues to be looked on queue
These issues will be addressed next:
Issues which have no takers yet
Please add here important bugs reported on kernel.org you'd like to see fixed.
All closed ath9k bugs
This is the list of all closed issues on ath9k on kernel.org.
Most common known issues
Minimal kernel requirements
You want at least these kernels to use ath9k:
The 2.6.31 kernel seems to have quite a few issues and fixes for them have been merged onto 2.6.32. If you cannot upgrade to 2.6.32 completely or use compat-wireless stable release for this kernel consider merging some of these patches:
We are working on propagating some of these fixes for future 2.6.31.y releases.
Please refer to Ubuntu kernel release to Mainline kernel release map to find out which package name you need as well as from what repository (called "pocket"). If you have no clue what was just described please read the Ubuntu Wireless documentation.
Hangs with PCI devices and SMP systems
This issue was due to a hardware limitation on our PCI devices whereby our device's FIFO queue got filled up and caused a loop. This issue is only present on our 11n PCI devices, its not present on our PCI-express devices nor our legacy 802.11abg devices.
The fix was to serialize read/writes – a spin_lock around each read and write. This fix is not performed for PCI devices or non-SMP systems. This fix is present in 2.6.29, 184.108.40.206 and 220.127.116.11.
DMA issues on 2.6.27
DMA issues were present on first release of 2.6.27, these issues were easily reproducible on MacBook Pros. This issue was fixed on 18.104.22.168.
Loss of connectivity after large file transfer on 2.6.28
This issue was fixed in 22.214.171.124, the issue was caused by the fact that ath9k was configured to ignore beacons and mac80211 expects them, after a large data transfer it is possible the beacons could have been missed and mac80211 detects a timeout of waiting for beacons or receiving data.
RX Poison issue
There was a race on how we dealt with the last RX buffer during reset/start/stop RX. This issue was reported through the bugzilla entry for the poison overwrite. This is now fixed and patches have been submitted for stable inclusion.
DMA stop failure issues
TX DMA stop failures
TX DMA stop failure issues should be cured as of 2.6.38, so use any kernel or stable compat-wireless release based on 2.6.38 or above. This has been fixed through this series of patches:
And this one fix will only be present as of 2.6.30, currently only on wireless-testing.git:
RX DMA stop failures
RX DMA stop failures are still being observed and this is being debugged. But there has been a lot of work to help with these issues:
The RX DMA issues are more severe given that if the PCU is confused and you assume that RX DMA was stopped properly but it was not the radio can still be programmed to operate on an already free'd DMA buffer. This can corrupt any DMA data from any other device driver. In fact the above poison issue was due to this same related issue.
FreeBSD Atheros ath driver bugs
If you are interested in reviewing FreeBSD 802.11 Atheros driver bugs see the FreeBSD ath bugs page