Date:	Thu, 22 Dec 2011 18:31:30 +0100
From:	Andreas Hartmann <andihartmann@...19freenet.de>
To:	Stanislaw Gruszka <sgruszka@...hat.com>
Cc:	Robert Hancock <hancockrwd@...il.com>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	linux-wireless <linux-wireless@...r.kernel.org>,
	users@...x00.serialmonkey.com
Subject: Re: [rt2x00-users] Poor performance and lockup with rt2800usb and
 Asus USB-N13 adapter

Am Thu, 22 Dec 2011 17:18:28 +0100
schrieb Stanislaw Gruszka <sgruszka@...hat.com>:

> On Tue, Dec 20, 2011 at 03:43:17PM +0100, Stanislaw Gruszka wrote:
> > I just discovered that at least some problems are related with power
> > save. After "iwconfig wlanX power off" I have pretty short ping times
> > and good throughput, both comparable with vendor driver. But I did not
> > check that on all adapters that I have yet.
> >
> > Looking a bit more at that seem we stop and wake queues several times
> > between sending each frame. Looks like that thing need to be optimized
> > in mac80211, or some parameters have to be setup properly by rt2x00 ...
> > 
> > Also rt2800 PCI and SOC have PS disabled by default ...
> 
> There is no bug with ping latencies when power save is enabled. Ping
> send packet every second, between that we put driver in power save
> mode (i.e. tell AP that we are sleeping and it has to buffer frame
> to us). When we send ping packet, we wake up and receive packet from
> a AP after longer time than in normal operation mode.
> 
> I did more testing here and I have one device that works very bad,
> no matter if PS is configured or not. It is 
> 
> phy6 -> rt2x00_set_chip: Info - Chipset detected - rt: 3071, rf: 0008, rev: 021c.

My device: 

phy0 -> rt2x00_set_chip: Info - Chipset detected - rt: 3572, rf: 0009, rev: 0221.

phy0 -> rt2x00lib_request_firmware: Info - Loading firmware file 'rt2870.bin'.
phy0 -> rt2x00lib_request_firmware: Info - Firmware detected - version: 0.236.


If CONFIG_RT2X00_DEBUG is switched on, I'm getting millions of entries
like these in messages:

[48570.815137] phy0 -> rt2800usb_txdone_entry_check: Warning - Data pending for entry 26 in queue 2
[48570.815150] phy0 -> rt2800usb_txdone_entry_check: Warning - Data pending for entry 26 in queue 2
[48570.815162] phy0 -> rt2800usb_txdone_entry_check: Warning - Data pending for entry 26 in queue 2
[48570.815174] phy0 -> rt2800usb_txdone_entry_check: Warning - Data pending for entry 26 in queue 2

or

[49404.459991] phy0 -> rt2800usb_txdone_entry_check: Warning - TX status report missed for queue 2 entry 32
[49404.462098] phy0 -> rt2800usb_txdone_entry_check: Warning - TX status report missed for queue 2 entry 36
[49404.462123] phy0 -> rt2800usb_txdone_entry_check: Warning - TX status report missed for queue 2 entry 37
[49404.463596] phy0 -> rt2800usb_txdone_entry_check: Warning - TX status report missed for queue 2 entry 40
[49404.463618] phy0 -> rt2800usb_txdone_entry_check: Warning - TX status report missed for queue 2 entry 41

not that often:

[49390.002284] phy0 -> rt2x00usb_watchdog_tx_status: Warning - TX queue 2 status timed out, invoke forced tx handler

I can easily force them running netperf in both directions (TCP_MAERTS
and TCP_STREAM). I would be happy with about 12 Mbit/s (that's
what I get with the ralink driver with good conditions stable over more
than just a few minutes) :-).

BTW: The patch in [1] breaks the driver completely (tested with
compat-wireless 3.1rc1).

> I'm going to investigate problems with that device, hopefully these are the
> same problems that Robert and Andreas have.

Thank you very much - it would be a great Christmas present if you
could repair this driver!

If you need some testing - I'll do it!


Kind regards,
Andreas

[1]
http://rt2x00.serialmonkey.com/pipermail/users_rt2x00.serialmonkey.com/2011-December/004345.html
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