[Prism54-devel] usb advances

[Jan Kiszka]

>>comment the lines resetting the USB device ; calling
>>usb_reset_device()
>>after the firmware upload never returns and causes a deadlock in the
>>module for some odd reason. Why should the USB be resetted ? Is it to
>>mimic the Windows driver's behaviour ? It seems unnecessary, at least
>>for my device.
> 
> 
> Actually Feyd wrote this part of the driver, i only fixed some
> endianess problems, some control logic problems related to the
> interrupt handling, allowed the resubmission of some packets during
> firmware upload. So for the actual meaning of the code, we should
> ask him first, but i think that indeed the intent was to mimic the
> windows driver.
> 
> I'll try without it on my devices, and remove it if unneeded, but i'm
> not sure we would not be hiding another problem. The kernel tells you
> nothing apart from this problem ? I've understood some things lately
> about usb and DMA, so there's bound to be some problems left in the
> code.
> 

Resetting is also still an open topic for ndiswrapper. I'm quite sure 
that it is an indication of some other error if you have to reset your 
device at all. There is a specific command in the Windows USB layer 
which at least the Linksys driver only uses when some error have occured.

With my WUSB54G on all of the available test systems around, I don't 
need it and we had a time where reset after init (firmware upload) was 
removed from the ndiswrapper source. This speeded up the loading and 
prevented other problems we had with the reset code. But as other 
device/driver combinations required it, it's now again part of the code 
(with fixed reset code).

One thing I watched quite often with ndiswrapper and also yesterday with 
JB's experimental driver is that the devices tends to hang up after 
restarting the driver producing various usb errors. The only solution 
then is a power-cycle.

> By the way, does anyone knows if it's possible to do a powerdown /
> powerup on an usb device on the command line in linux ? Better than
> unplugging / replugging it by hand, which i often have to do...
> 

I haven't found some software "power switch" as well. My USB connectors 
already have half of their typical life time behind. ;)

Jan
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/x-pkcs7-signature
Size: 4760 bytes
Desc: S/MIME Cryptographic Signature
Url : http://prism54.org/pipermail/prism54-devel/attachments/20041219/c2e4c4cf/smime.bin