Vojtech Pavlik wrote: >On Tue, Apr 11, 2006 at 08:52:17AM -0600, Michael Downey wrote: > > > >>>The reason is that it was originally intended for devices which don't >>>issue huge numbers of reports in one go, and 64 was supposed to be >>>'large enough' for userspace to be able to empty the buffers as the data >>>are coming from the device. >>> >>>Moving to 512 is not a big problem, except for memory usage. >>> >>>However, I'd suggest using libusb/libhid instead here, since the hiddev >>>interface is really inadequate for uses like this. >>> >>> >>> >>> >>> >>The problem with libhid is that it is a GPL licenced library not LGPL so >>I can't use it. Otherwise that was my initial plan. Also the benifit of >>using hiddev is that I don't have to install another library onto the >>system. I could try using libusb but it looked like I would have to >>basically replicate a lot of what libhid does. >> >>So is the memory usage a concern? >> >> > >Yes, it's a waste on most systems. If it could be done dynamically >(based on the number of usages in the largest report), that'd be >perfect. > > > Do you or anyone else know the code well enough to make a change like that? I've really only spent maybe a half a day looking at the code and I can't say I'd be overly comfortable at making that kind of change. I believe the hid-core does something similar when it determines the size to allocate for it urb. The increase to 512 would use ~12K per device whereas we are currently using about 1K per device. Do a lot of devices use hiddev?
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