lkml.org 
[lkml]   [1997]   [Sep]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: VIC and Matrox Meteor
    Date
    >   1) alloc some kernel memory and allow the program to mmap this. The
    > bttv readme states some drivers do it this way, but allocate the
    > memory at boot time (which is a no-no for a module of cource).
    > Does kmalloc()ed memory work too?

    kmalloc can never guaratee getting you a large contiguous block. The current
    bttv can handle scattered pages I think (the chip can) so you could vmalloc
    a buffer and mmap all the pages (messy). The mm trick stuff is in Linux ATM
    for 2.0, but not ported to 2.1.x yet.

    > 2) Take userland memory and lock it. There is a comment in the source
    > which says it doesn't work yet (i.e. the module can't lock the
    > memory). Is this still true?
    > A experimental grabber program uses mlock() to do this job, but
    > I don't like this becauce mlock() requires root priviliges.

    I'd been meaning to try making the grabber call the sys_mlock calls innards
    directly and touch each page but haven't had time yet. Im currently turning
    the bt848 stuff into a generic video for linux layer


    \
     
     \ /
      Last update: 2005-03-22 13:40    [W:0.034 / U:0.584 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site