what kind of device is that? USB/PCI etc based? for many USB devices, u just need userspace tools. For eg: 1. libusb-devel (or libusb-dev....depending on the distros), or libpci etc....for writing userspace application to talk to the device. 2. add udev rules. (for eg, this url: http://wiki.lynxworks.eu/misc/e1550 shows how to add a new device in different distro). The application that issued the read() in this case is usb_modeswitch. Download the sourcecode from: http://www.draisberghof.de/usb_modeswitch/ and see how it uses libusb+read/write/open to talk to the device. On Thu, Sep 17, 2009 at 2:59 PM, Leonidas . <leonidas137@xxxxxxxxx> wrote: > > > Hi list, > > I know that introducing/using new ioctls is frawned upon by the community. > They might still be needed for controlling various hw parameters, Just > wanted > to understand the data transfer side of ioctls with a use case. > > E.g. My kernel module needs to pass a buffer of 1-2Mb to userspace > whenever user requests. The buffer will contain different kind of data > depending > on different commands i.e. assume that I maintain 3 types of buffers in my > module. > > Now, with ioctls it is much easiler to get the buffer to userspace simply by > issusing > different commands. But if I have to achive the same functionality using > read() call > how would I do it? Meaning ioctl kind of multiplexes the things which might > be > needed in some cases. How would I do this kind of stuff with read()? By > having 3 > different minor devices and issuing read() on 3 devices for getting 3 > buffers? > > I am not looking for anyother mechanism of trasnfering data to userspace as > of now > since this data would be really sporadic. I have to choose between ioctl and > read. > > -Leo. > -- Regards, Peter Teoh -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
