[rt2x00-users] rt2x00: status update regarding txdone handling

Ivo Van Doorn ivdoorn at gmail.com
Fri Jul 30 21:06:15 AEST 2010


On Fri, Jul 30, 2010 at 12:43 PM, Helmut Schaa
<helmut.schaa at googlemail.com> wrote:
> Am Donnerstag 29 Juli 2010 schrieb Ivo Van Doorn:
>> On Thu, Jul 29, 2010 at 6:30 PM, Helmut Schaa
>> <helmut.schaa at googlemail.com> wrote:
>> > Am Donnerstag 29 Juli 2010 schrieb Ivo Van Doorn:
>> >> Hi,
>> >>
>> >> > I'm still fighting with the txdone handling in rt2800pci. Sometimes the tx
>> >> > queues get stuck. It took me a few days but it seems as if the TX_STA_FIFO
>> >> > register limitation to hold max 16 entries is causing this problem.
>> >>
>> >> Weird, for rt2800usb this doesn't seem to be the problem. The queue locks
>> >> up even when I continuously read the TX_STA_FIFO register.
>> >
>> > Maybe I should add that this behaviour only happens when running iperf
>> > from the SoC board to an associated client. And the host CPU utilization
>> > is near to 100%.
>>
>> Ah ok, well I haven't managed to get iperf working on my system yet,
>> so I can't test that. But since the queue locks up regardless of CPU and
>> TX_STA_FIFO status, it might be a different problem (perhaps even for SoC).
>
> Hmm, yeah. If you look at the queue state in debugfs is the number of available
> entries smaller than the thershold and thus the queues are stopped? At least
> that's the case I observe here (because not all frames get their appropriate tx
> status).

But that means the problem can be solved by rekicking the queue
once you read the TX_STA_FIFO register.

Ivo




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