Messages in this thread | | | Date | Sat, 28 Mar 1998 12:15:01 +0000 (GMT) | From | Chris Evans <> | Subject | Re: GGI Project Unhappy On Linux |
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On 28 Mar 1998, Jes Degn Soerensen wrote:
> There is nothing the prevents you from pipelining the blit operations > in user space as well and/or start doing other things while `waiting' > for a blit operation to finish.
Jes,
The `waiting' as you put it is the precise problem, as it is a polling operation, maybe something like
(while !(inw(gfx_base+status) & status_acceldone)
Modern graphics cards will happily generate an interrupt upon the completion of an accelerated operation, or even a "queue empty" event when a queue of commands has been processed. The kernel has access to interrupts and interrupt handlers. Userspace doesn't, although maybe a kernel interrupt -> signal userspace gateway could be set up with minimal code.
The point is, there are certain performance enhancing operations on cards that X, as a user process, will _never_ have access to without kernel support.
Chris
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