Arch Linux

Description: Prior to upgrade from kernel26-2.6.38-ARCH, wireless performance was excellent I had a near non existant Invalid misc value and no Tx excessive retries from the output of iwconfig.
Post update to 2.6.39 there has been regression in bit rate performance and a large increase in errors :

output of iwconfig post 2.6.39 update:
wlan0 IEEE 802.11abgn ESSID:""
Mode:Managed Frequency:2.412 GHz Access Point:
Bit Rate=24 Mb/s Tx-Power=14 dBm
Retry long limit:7 RTS thr:off Fragment thr:off
Power Management:off
Link Quality=55/70 Signal level=-55 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:5 Invalid misc:33419 Missed beacon:0

output of dmesg |grep 4965 :

[ 5.842556] iwl4965: Intel(R) Wireless WiFi 4965 driver for Linux, in-tree:
[ 5.842578] iwl4965: Copyright(c) 2003-2011 Intel Corporation
[ 5.842580] Registering 4965 rate control operations
[ 5.842643] iwl4965 0000:03:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17
[ 5.842651] iwl4965 0000:03:00.0: setting latency timer to 64
[ 5.842678] iwl4965 0000:03:00.0: Detected Intel(R) Wireless WiFi Link 4965AGN, REV=0x4
[ 5.915174] iwl4965 0000:03:00.0: device EEPROM VER=0x36, CALIB=0x5
[ 5.915192] iwl4965 0000:03:00.0: Tunable channels: 11 802.11bg, 13 802.11a channels
[ 5.915451] iwl4965 0000:03:00.0: irq 48 for MSI/MSI-X
[ 6.017997] iwl4965 0000:03:00.0: loaded firmware version 228.61.2.24
[ 6.401528] ieee80211 phy0: Selected rate control algorithm 'iwl-4965-rs'



output of lspci | grep 4965 :
03:00.0 Network controller: Intel Corporation PRO/Wireless 4965 AG or AGN [Kedron] Network Connection (rev 61)