[ath9k-devel] Stable Version for ath9k_htc in AP Mode?

[Oleksij Rempel <linux@rempel-privat.de>]

Am 12.05.2014 15:11, schrieb Peter Stuge:
> Oleksij Rempel wrote:
>> From dmesg i see that, to one USB 1.1 root-hub attached two device,
>> ath9k_htc and GobiNet. GobiNet was recognised as eth1 + 3 x ttyUSB.
>> IMO, it is a lot for one USB 1.1.
> 
> True as that may be, if there is a bandwidth requirement for the
> interface to function correctly and the USB protocol being used does
> not guarantee that bandwidth (only control+interrupt transfers could
> do it in a meaningful way, and they are rather low bandwidth) then
> the USB stack would have to allow the driver to reserve bus time, and
> the driver would have to make a reservation to successfully handle
> worst-case load.
> 
> That's not neccessarily a small change. :\

I tested ath9k-htc on many different usb host controllers (not usb 1.1),
and noticed that most USB 2.0 controllers need some *msecs* to transfer
one Interrupt package to the adapter or at least to get ACK signal. USB
3.0 was transferring same package in some *usecs*. The results should be
similar for both controller, but it is not the case. Even different USB
2.0 controller was performing differently.

This big difference is responsible for extremely long scan time on
ath9k_htc on USB 2.0. Since Interrupt Endpoints are heavily used on this
devices, reducing bandwidth and/or increasing transfer time for
Interrupt traffic will be critical.

Best indicator for this issue would be, disabling LED subsystem to get
better stability. What, according to Aaron, is the case.

-- 
Regards,
Oleksij

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