Messages in this thread | | | Date | Tue, 30 Mar 1999 04:18:02 -0800 | From | David Miller <> | Subject | Re: Address spaces on a i386 - Getting Confused |
| |
From: Paul Sargent <Paul.Sargent@3dlabs.com> Date: Tue, 30 Mar 1999 13:12:25 +0100
So presumably the other option is to allocate kernel memory and then pass a pointer to it back to user space. Is that possible?
The user can't get at it, because it is in kernel space which is protected from user accesses. If we allowed that, any user could just set his uid to zero and become root :-)
I think unless you are willing to go into the hair the bttv driver does, you're going to need to have the device put it into a kernel buffer and then copy it into user space.
Since you're so adament about DMA'ing directly into user space, you've piqued my interest, what does this card do and what is the application? Video capture or 3d texture mapping?
Later, David S. Miller davem@redhat.com
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |