Messages in this thread |  | | | From | (Alan Cox) | | Subject | Re: VIC and Matrox Meteor | | Date | Fri, 19 Sep 1997 09:07:27 +0100 (BST) |
| |
> 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
|  |