On Mon, 4 Aug 2003, Tuukka Toivonen wrote: > On Mon, 4 Aug 2003, Trent Piepho wrote: > > >The waste of memory argument only works if you ignore user space. If the > >driver doesn't provide multiple buffers, then the application has to. The > >buffers are still there, they've just moved. > > You missed some messages? Yes, the buffers are still there, internal to the > driver. They just aren't mmapped because the data in the internal buffers > is in format which is not understood by any user application anyway > (except my special test program). You're right, I missed that and now it makes a lot more sense. You do have multiple buffers in your driver, you just can't export them to userspace because they're in a non-standard format. I take it you do the format conversion and copying into the mmapped buffer on the sync call? Have you considered doing the format conversion earlier? Have just one bounce buffer for the hardware, and convert the data as soon as the hardware buffer is full and an empty mmap buffer is available?
