[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
SVGA cards on PCI
- To: Mailing List Recipients <pci-sig-request@znyx.com>
- Subject: SVGA cards on PCI
- From: Noam Halevy <noamh@msil.sps.mot.com>
- Date: Tue, 10 Dec 1996 07:27:51 +0200 (IST)
- Resent-Date: Tue, 10 Dec 1996 07:27:51 +0200 (IST)
- Resent-From: pci-sig-request@znyx.com
- Resent-Message-Id: <"sv01l.0.MW.EOFho"@dart>
- Resent-Sender: pci-sig-request@znyx.com
Hello,
I am sorry if this is a very basic question for you video people ...
A video card which sits on the PCI has to refresh the screen at some rate.
The screen data is (I guess) in it's intrnal vram.
My question is:
when the processor needs to change the data, how does it pass it to the
video card memory ? Does it use the card's DMA (which would cause long READ
bursts on the PCI which is bad for performance) or does it use it's own DMA
for the job ?
In any case, I assume that the video data is never cached by the processor
and that there is no copy of the video ram in the system memory.
Thanks very much for any response.
Best regards,
Noam Halevy
email: noamh@msil.sps.mot.com
Tel: 972-3-590534
MSIL
______
/ Motorola Semiconductor Israel.
/________________________________
à Í