[Arm-netbook] Allwinner 2.6.36 kernel and poor USB performance

[nikk gitanes]

Hi, I'm working on Allwinner A10 Android 2.3 tablet connected with many USB devices,
and found very poor USB performance on 2.6.36 kernel.

My device have only one OTG port, so I attach self-powered USB Hub to it.

Connected USB devices are: USB DAC, PL2303 based GPS, DVB-T Tuner, Bluetooth stick, 3G Modem.

I have no major issues with soundcard and dvb, all other devices also work fine alone, BUT
when 3G or BT device have activity (for example, I enable bluetooth, or plug 3G modem and it establishing 3G connection),
sound, transferred to USB DAC, goes choppy, and not listenable at all.

After some debugging (thanks dmesg), I realise that it's all related to allwinners' USB host driver.

...
<7>[  597.740000] 	[ fire_audio_urb : 216 ] 
<6>[  597.750000] WRN:L2286(drivers/usb/sun4i_usb/hcd/core/sw_hcd_host.c):ERR: sw_hcd_host_rx, end 1 RX proto error(0x4)
<6>[  597.760000] WRN:L2286(drivers/usb/sun4i_usb/hcd/core/sw_hcd_host.c):ERR: sw_hcd_host_rx, end 1 RX proto error(0x4)
<6>[  597.770000] WRN:L2286(drivers/usb/sun4i_usb/hcd/core/sw_hcd_host.c):ERR: sw_hcd_host_rx, end 1 RX proto error(0x4)
<7>[  608.940000] 	[ fire_audio_urb : 216 ] 

DVB doesn't work also, if connected to 2nd usb hub, connected to 1st one: 

...
<7>[  396.040000] 	[ fire_audio_urb : 216 ] 
<6>[  407.140000] WRN:L3142(drivers/usb/sun4i_usb/hcd/core/sw_hcd_host.c):ERR: not support type(1)
<6>[  407.140000] WRN:L3142(drivers/usb/sun4i_usb/hcd/core/sw_hcd_host.c):ERR: not support type(1)
<6>[  407.140000] WRN:L3142(drivers/usb/sun4i_usb/hcd/core/sw_hcd_host.c):ERR: not support type(1)
<6>[  407.150000] WRN:L1867(drivers/usb/sun4i_usb/hcd/core/sw_hcd_host.c):ERR: sw_hcd_host_tx, urb is NULL
<7>[  407.180000] 	[ fire_audio_urb : 216 ]

There are many other errors from sw_hcd_host.c in various conditions.

Does this mean driver is incomplete? Do you have issues with USB devices on your hardware?