On Tue, 21 May 2002 19:34, Morens Jaques wrote: > what is the criterion for a user mode driver or a kernelmode driver?? > or is it possible to write two differnt driver for all kind of usb > devices?( no matter which transfer type the device use) IMNSHO: There isn't a strict definition, and some devices can be supported by either userspace or kernel space, especially with some of the newer kernel changes. Generally, if the driver needs a lot of kernel support (eg a networking driver, which relies on the kernel IP stack or a storage device that relies on the kernel SCSI stack) then you are better off doing it in kernel space.
If the driver API is normally implemented in the kernel (eg virtual serial or parallel port devices, or input devices), then this is also a good reason for a kernel implementation, since applications will expect that they can use the same API. If there is no common API, or you can easily avoid kernel space, then you should. Firmware loading is sometimes used as an example of something that should be done in userspace (although there are some subtle issues associated with swap space), and still camera drivers are often done in userspace too. Note that some devices may need both - the at76c503a wireless usb networking device that I sometimes work on has a userspace firmware loader, and a kernel mode device driver. If you need more info, you really need to provide a concrete example. Brad -- http://conf.linux.org.au. 22-25Jan2003. Perth, Australia. Birds in Black. _______________________________________________________________ Don't miss the 2002 Sprint PCS Application Developer's Conference August 25-28 in Las Vegas -- http://devcon.sprintpcs.com/adp/index.cfm _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
