(125points) Manually Configuring IRQs under XP
Posted on 2004-09-11
I'll start by telling you that you may use all the tech-terms you want, no problem. I've been using computers since 92 and am not afraid of difficult solutions.
The problem I'm currently having is due to XP's automatic resource assignment. XP uses a new formula, "don't rebalance IRQs even if need be, it's too "risky"". "Risky" being a word taken from the MSDN entry for how IRQ assignment works on XP. This means that IRQs stay once they've been assigned.
[Note: There is one "solution" that I don't want to hear from. You can change the HAL from "ACPI" to "Standard PC". However, Microsoft clearly states that doing so WILL create an instable system. The reason being that several drivers required for "Standard PC" are not installed (they are only installed when choosing "Standard PC" during XP setup), and you'll still have leftovers from the "ACPI" HAL. So please, no comments about how I should change the HAL to "Standard PC", it's critical that this computer is able to run 24/7.]
Moving on to the problem. I have 3 VERY high-bandwidth devices sharing IRQ 10. Namely:
- Radeon 9600 XT [graphics]
- PDI Deluxe [professional video capture card (rgb), immense bandwidth requirement]
- Pinnacle PCTV [tv tuner, used to watch TV on your computer]
The latter (PCTV) is able to co-exist with the Radeon. While the Radeon recieves and outputs graphics, the PCTV can happily capture video at the same time. The PCTV video stream is compressed and not high-bandwidth.
However, if I start capturing RGB-video using the PDI Deluxe, the bandwidth is far from enough. The bus drops 10 captured frames per second due to overload (resulting in jerky motion).
After a while the graphic card locks up due to dropped data that SHOULD have reached the Radeon if not the bus had been so overloaded.
"ATI VPU Recover" sometimes manages to reinitialize and save the card so that I get enough visual feedback for a reboot.
The CPU load never goes above 50% and there is no real heat in the system so those two can be ruled out. I definitely believe that the IRQ sharing for these devices, sending extremely high-bandwidth data back and forth simultaneously over the same channel (IRQ 10), is causing the problems.
I need to solve this before monday as I'll be needing the video capture at a conference. My question is, what can I do to spread the IRQs? I am using Windows XP Professional (English).
Steps taken so far:
* I tried to free up some IRQs by disabling the COM ports and LPT port, which gave me 3 new IRQs. But as mentioned above (from MSDN), Windows XP does not rebalance IRQs even if you free up some more.
* Googled for a few hours.
* I'd like to keep the card structure in the box (not move them around unless it's not possible to fix this software-wise). The reason being that this is a HTPC (Home theater PC) where cards are arranged in this order: Audio Out (5.1), Audio In (24/96), Video In (PDI Deluxe), TV In (PCTV), Video Out (Radeon) with a printed label that would have to be completely redone.