Re: DWA-160

Re: DWA-160

[Christian Lamparter]

On Tuesday 14 June 2011 15:45:28 ShawnG wrote:
> I have been seeing strange stuff with the DWA-160 ver A2. Can you recommend
> another USB Wifi stick to replace ?
Depends. I've to say that I'm slightly biased towards Atheros products.
Although, Ralink and Realtek have interesting products as well.

So, if you don't need 5GHz then I would go with a ath9k_htc device
like: TL-WN821N *V3* [Note: V3 is important, because previous
versions are based on AR9170, however they stopped making them
some time ago [6-7 months?], so it should be safe to assume they've
disappeared from retail stores by now.] 

if you do need 5GHz, then it might be a good idea to ask:
George Nychis <gnychis@cmu.edu>

He has done some testing with several 5GHz capable ath9k_htc devices
from different vendors and might know which are well suited.

Regards,
	Chr

Re: DWA-160

[Christian Lamparter]

On Tuesday 14 June 2011 16:17:40 ShawnG wrote:

> Is it ok to assume then that future work on CARL9170 will be minimal?
I'm thinking of adding support for cfg80211's new wakeup-on-wlan triggers
and some code to do clear channel assessments in the future. Also, some
resources will probably go into the userspace carlu code as well. So it
answer depends whenever you are interested in those topics or not.

Regards,
	Christian

Re: DWA-160

[Christian Lamparter]

On Tuesday 14 June 2011 16:47:45 ShawnG wrote:
> I forgot to ask this, does the AR9170 hardware FCS calculation have a bug,
> because we see garbage packets quite frequently?

Depends on how you operate the device
[as client or AP, with 11n-draft or just b/g].

Obviously, if you use HW crypto offload [default] on one interface and
capture frames on an extra monitor interface on the same device, the
FCS will always be wrong for protected data frames  because the HW
has already decrypted the frame, but left the original FCS
[for the encrypted frame]  in place.

Also, you should tell your capture tool not to enable promisc mode
[most enable it by default], because this also affects the FCS check.

So much for the "duh!" cases.

However, this might not be the whole story, in fact I've seen weird data frames
as well [with different HW, but no matter]. I don't think the FCS check per se is
buggy. The hardware seems to receive and verify the frames just fine, but
somehow the frame's content get corrupted along the way to the driver.

[Note: The reason why I think this is more likely is because the
hardware also "sends" occasionally garbage frames but with a
correct FCS!

this was detected by a case we had a while ago:
mac80211: ignore non-bcast mcast deauth/disassoc frames"]

What I don't know if behavior is caused by a incorrect register value
somewhere, or by a hardware bug.

However,  if you have a "normal" PC,  you can always set
nohwcrypt=1. This will fix the issue for good, because the
garbage data frames will then be dropped by the message
integerty check.

Regards,
	Chr

Re: DWA-160

[Thomas Novin]

On Tue, Jun 14, 2011 at 4:12 PM, Christian Lamparter
<chunkeey@googlemail.com> wrote:
> On Tuesday 14 June 2011 15:45:28 ShawnG wrote:
>> I have been seeing strange stuff with the DWA-160 ver A2. Can you recommend
>> another USB Wifi stick to replace ?
> Depends. I've to say that I'm slightly biased towards Atheros products.
> Although, Ralink and Realtek have interesting products as well.
>
> So, if you don't need 5GHz then I would go with a ath9k_htc device
> like: TL-WN821N *V3* [Note: V3 is important, because previous
> versions are based on AR9170, however they stopped making them
> some time ago [6-7 months?], so it should be safe to assume they've
> disappeared from retail stores by now.]
>
> if you do need 5GHz, then it might be a good idea to ask:
> George Nychis <gnychis@cmu.edu>
>
> He has done some testing with several 5GHz capable ath9k_htc devices
> from different vendors and might know which are well suited.

I asked Geoprge Nychis and got a reply.

He recommends http://www.wikidevi.com/wiki/Sony_UWA-BR100 which has
AR7010 + AR9280 chipset. Almost the same as  TL-WN821N v3 but
secondary chip is a little different as the TP-Link has AR9287.

Found them on Amazon for $75. I don't know if these works
out-of-the-box or that maybe you have to edit the source a little bit
to get the IDs supported? Well doesn't really matter for me, easy to
fix.

Rgds//Thomas

Re: DWA-160

[Thomas Novin]

On Sat, Jun 18, 2011 at 11:41 AM, Thomas Novin <thomas@xyz.pp.se> wrote:
> He recommends http://www.wikidevi.com/wiki/Sony_UWA-BR100 which has
> AR7010 + AR9280 chipset. Almost the same as  TL-WN821N v3 but
> secondary chip is a little different as the TP-Link has AR9287.
>
> Found them on Amazon for $75. I don't know if these works
> out-of-the-box or that maybe you have to edit the source a little bit
> to get the IDs supported? Well doesn't really matter for me, easy to
> fix.

I didn't get the UWA-BR100 with Atheros chip but instead with Ralink
chip. There are (at least) two versions of it.

http://www.wikidevi.com/wiki/Talk:Sony_UWA-BR100
http://www.wikidevi.com/wiki/Buffalo_WLI-UC-AG300N

Maybe TP-Link TL-WN821Nv3 is a better choice.

http://linuxwireless.org/en/users/Drivers/ath9k_htc/devices

Rgds

Re: DWA-160

[Thomas Novin]

On Tue, Jun 28, 2011 at 11:48 AM, Thomas Novin <thomas@xyz.pp.se> wrote:
> I didn't get the UWA-BR100 with Atheros chip but instead with Ralink
> chip. There are (at least) two versions of it.
>
> http://www.wikidevi.com/wiki/Talk:Sony_UWA-BR100
> http://www.wikidevi.com/wiki/Buffalo_WLI-UC-AG300N
>
> Maybe TP-Link TL-WN821Nv3 is a better choice.
>
> http://linuxwireless.org/en/users/Drivers/ath9k_htc/devices

Actually, I got the one with Atheros (if there even is one with
Ralink, I think that might just be a mixup with USB IDs). Some
confusing info on wikidevi.com lead me wrong.

It doesn't work out-of-the-box with compat-wireless but I think it
will soon. I subscribed to the ath9k-devel mailinglist and got help
with a patch to the source of ath9k_htc. After a little fix, the
driver works with UWA-BR100.

Discussion + patch here:

https://lists.ath9k.org/pipermail/ath9k-devel/2011-June/006441.html

Rgds//Thomas

Ps. I get about 60-80Mbps upstream and 50Mbps downstream connected to
my Ubiquiti Power AP-N w/ 20MHz channel width.