From: wayne (wayne_at_its.noneofyour.info)
Date: 2002-06-10 11:37:27 UTC
> OK, this is an issue with power saving mode and buffering packets to
> stations. I haven't tested the driver with stations using PS for a
> long time. It did not apparently survive
> PRISM2_USE_CMD_COMPL_INTERRUPT related changes without breaking..
>
> The driver tried to setup STA's TIM bit just after performing transmit
> command. However, with cmd completion events, the next command should
> not be started before the previous one has completed. This leads to
> the reported timeouts. In addition, there's another problem that can
> occur if the station has many buffered frames and it moves into non-PS
> mode.
>
> I have not fixed those two cases. I used busy waiting in set_tim, but
> this could at some point be replaced with something like delayed
> command queue that would be handled after command completion event.
>
> These fixes seemed to take care of all the problems I saw in my PS
> test setup. Please let me know, if there are still problems with the
> fixed version. It is available as CVS snapshot from
> http://hostap.epitest.fi/.
>
I've downloaded and compiled the snapshot. There was a warning during compilation that 'SETVAL" was being re-defined in prism2.c:2079. Initial definition is in /usr/src/linux/include/linux/sem.h:15.
After installing the driver, dmesg now reports the following:
prism2_set_tim after buffer_count 0 failed; PS=0
Re-setting TIM for aid 1
wlan0: TIM: timeout on waiting pending transmit command..
prism2_set_tim after buffer_count 0 failed; PS=0
wlan0: TXEXC - fid=0x0301 - status=0x0001 ([RetryErr]) tx_control=000c
retry_count=0 tx_rate=110 fc=0x0a08 (Data::0)
addr1=00:05:5d:ee:50:50 addr2=00:05:5d:5b:dd:f9 addr3=00:05:5d:5b:dd:f9
wlan0: STA 00:05:5d:ee:50:50 TX rate lowered to 55
Re-setting TIM for aid 1
wlan0: STA 00:05:5d:ee:50:50 TX rate raised to 110
wlan0: TIM: timeout on waiting pending transmit command..
prism2_set_tim after buffer_count 0 failed; PS=0
Re-setting TIM for aid 1
wlan0: TIM: timeout on waiting pending transmit command..
prism2_set_tim after buffer_count 0 failed; PS=0
Re-setting TIM for aid 1
wlan0: TIM: timeout on waiting pending transmit command..
prism2_set_tim after buffer_count 0 failed; PS=0
Re-setting TIM for aid 1
wlan0: TIM: timeout on waiting pending transmit command..
prism2_set_tim after buffer_count 0 failed; PS=0
Re-setting TIM for aid 1
wlan0: TIM: timeout on waiting pending transmit command..
prism2_set_tim after buffer_count 0 failed; PS=0
Re-setting TIM for aid 1
No more space in this STA's PS mode buffer No more space in this STA's PS mode buffer No more space in this STA's PS mode buffer No more space in this STA's PS mode buffer No more space in this STA's PS mode buffer No more space in this STA's PS mode buffer No more space in this STA's PS mode buffer No more space in this STA's PS mode bufferwlan0: TIM: timeout on waiting pending transmit command.. prism2_set_tim after buffer_count 0 failed; PS=0 Re-setting TIM for aid 1
I'm not sure whether it's relevent but I don't have power management enabled for this device. iwconfig reports that power management is off.
Also when transmitting at full speed the dmesg log fills with "wlan0: INFDROP event" messages.
Cheers
Wayne