[mythtv-users] PCI/AGP Latency

[Hamish Moffatt]

On Tue, Jul 20, 2004 at 03:10:26PM -0600, John Patrick Poet wrote:
> Here is an interesting article on PCI/AGP latency:
> http://www.geocities.com/phileosophos/tech/pcilatency.html

I think some of the information in the article is wrong. (Maybe I'm
wrong though.) AGP is a seperate bus than PCI, so the high latency
value for the AGP card won't hurt the sound and network devices.

Similarly, many of the on-board peripherals like IDE, sound, network 
etc are on a separate PCI bus than the PCI slots. lspci from my MythTV
system (Gigabyte 7N400 Pro2 motherboard) is below. You can see the
devices 0000:00* are the on-board devices on one PCI bus (66 MHz PCI); 
the PCI slots are 0000:01* (33 MHz PCI) and the AGP is 0000:02*.

0000:00:00.0 Host bridge: nVidia Corporation nForce2 AGP (different version?) (rev c1)
0000:00:00.1 RAM memory: nVidia Corporation nForce2 Memory Controller 1 (rev c1)
0000:00:00.2 RAM memory: nVidia Corporation nForce2 Memory Controller 4 (rev c1)
0000:00:00.3 RAM memory: nVidia Corporation nForce2 Memory Controller 3 (rev c1)
0000:00:00.4 RAM memory: nVidia Corporation nForce2 Memory Controller 2 (rev c1)
0000:00:00.5 RAM memory: nVidia Corporation nForce2 Memory Controller 5 (rev c1)
0000:00:01.0 ISA bridge: nVidia Corporation nForce2 ISA Bridge (rev a4)
0000:00:01.1 SMBus: nVidia Corporation nForce2 SMBus (MCP) (rev a2)
0000:00:02.0 USB Controller: nVidia Corporation nForce2 USB Controller (rev a4)
0000:00:02.1 USB Controller: nVidia Corporation nForce2 USB Controller (rev a4)
0000:00:02.2 USB Controller: nVidia Corporation nForce2 USB Controller (rev a4)
0000:00:06.0 Multimedia audio controller: nVidia Corporation nForce2 AC97 Audio Controler (MCP) (rev a1)
0000:00:08.0 PCI bridge: nVidia Corporation nForce2 External PCI Bridge (rev a3)
0000:00:09.0 IDE interface: nVidia Corporation nForce2 IDE (rev a2)
0000:00:1e.0 PCI bridge: nVidia Corporation nForce2 AGP (rev c1)
0000:01:06.0 Multimedia controller: Philips Semiconductors SAA7146 (rev 01)
0000:01:07.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8029(AS)
0000:01:09.0 Multimedia video controller: Brooktree Corporation Bt878 Video Capture (rev 11)
0000:01:09.1 Multimedia controller: Brooktree Corporation Bt878 Audio Capture (rev 11)
0000:02:00.0 VGA compatible controller: nVidia Corporation NV18 [GeForce4 MX 440 AGP 8x] (rev a4)


Hamish
-- 
Hamish Moffatt VK3SB <hamish at debian.org> <hamish at cloud.net.au>