Drivers in kernel of user space?

[Brian K. White]

----- Original Message ----- 
From: "Karolis Tamutis" <karolis.t at gmail.com>
To: <freebsd-usb at freebsd.org>
Sent: Friday, August 19, 2005 6:31 PM
Subject: Drivers in kernel of user space?


Should drivers for an usb device (or a series of devices) be developed
in kernel space or in user space, now that we have such cross platform
ported libraries as libusb? What's your opinion.

-------------------

Isn't there problems with libusb that make it a big compromize ?

For example, last I knew (admittedly several months ago) the reason my 
canoscan lide scanner was so horrendously slow in linux was because it used 
libusb and libusb didn't have a way to do the type of transfer the scanner 
really needs. Something about async vs sync? I know in freebsd I have used 
the same scanner both using the in-kernel /dev/uscanner0, and libusb. I 
didn't do these things at the same time or on the same machine, nor had I 
yet tried to do a high quality scan that exposed the slowness compared to 
the same scan in windows. So I never tried a direct comparison of speeds 
under the different drivers on the same hardware doing the same scan.
Been meaning to since the scanner happens to be on a freebsd box again and I 
have uses for the scanner again.

Brian K. White  --  brian at aljex.com  --  http://www.aljex.com/bkw/
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