iwlwifi firmware network hangup with 2.6.28.4-1

[vip]

After a high network load (it can be done in less than 30 secs), dmesg:
[ 722.502274] iwlagn: Microcode SW error detected. Restarting 0x82000000.
[ 724.714102] iwlagn: Can't stop Rx DMA.
[ 725.724929] iwlagn: No space for Tx
[ 725.724937] iwlagn: Error sending SENSITIVITY_CMD: enqueue_hcmd failed: -28
[ 725.724941] iwlagn: SENSITIVITY_CMD failed
[ 725.942810] Registered led device: iwl-phy0:radio
[ 725.942849] Registered led device: iwl-phy0:assoc
[ 725.942888] Registered led device: iwl-phy0:RX
[ 725.942923] Registered led device: iwl-phy0:TX

and the network is not working.
To renew a connection: service network restart, but when net load raises, that situation repeats.

Th, i686, kernel from ftp: kernel-pae-2.6.28.4-1.i686 and custom (--with pae, kernel-pae-2.6.28.4-1.i686).

iwlwifi-4965-ucode-228.57.2.21-2.noarch

[vip (piotr-budny)]

It seems, that kernel-pae-2.6.27.14-2.i686 detects SW error too, but restarts (something):
[ 1518.994319] wlan0: RX ReassocResp from 00:0x:xx:xx:xx:xx (capab=0x411 status=0 aid=2)
[ 1518.994327] wlan0: associated
[ 1573.769917] iwlagn: Microcode SW error detected. Restarting 0x2000000.
[ 1576.972674] iwlagn: Can't stop Rx DMA.
[ 1577.186476] Registered led device: iwl-phy0:radio
[ 1577.186535] Registered led device: iwl-phy0:assoc
[ 1577.186574] Registered led device: iwl-phy0:RX
[ 1577.186612] Registered led device: iwl-phy0:TX
[ 1577.196630] wlan0: authenticate with AP 00:0x:xx:xx:xx:xx

[vip (piotr-budny)]

Upgrading to iwlwifi-4965-ucode-228.57.2.23-1.noarch may help.

[vip (piotr-budny)]

Reopen. Affects also 2.6.28.5_pae-1 with iwlwifi-4965-ucode-228.57.2.23-1.noarch

[vip (piotr-budny)]

Could be a temporary resolution:
http://www.fell.it/2009/02/18/microcode-swhw-error/