I noticed that with my HP photosmart scanner & Linux, sane_read() only
reads a maximum of 4 kB. Is there a connection with PIPE_BUF as
defined in linux/limits.h? I like to know how to get more then 4 kB
per read. I tried recompiling the kernel with a larger PIPE_BUF but
then all sorts of things go wrong (like X11 won't starting anymore).