Interesting discussion at Guru3d about Line based vs message signal-based interrupts
Checking for PCI devices working in MSI-mode.
Go to Device Manager. Click in menu "View -> Resources by type". Expand "Interrupt request (IRQ)" node of the tree. Scroll down to "(PCI) 0x... (...) device name" device nodes. Devices with positive number for IRQ (like "(PCI) 0x00000011 (17) ...") are in Line-based interrupts-mode. Devices with negative number for IRQ (like "(PCI) 0xFFFFFFFA (-6) ...") are in Message Signaled-based Interrupts-mode.
Trying to switch device to MSI-mode.
You must locate device`s registry key. Invoke device properties dialog. Switch to "Details" tab. Select "Device Instance Path" in "Property" combo-box. Write down "Value" (for example "PCI\VEN_1002&DEV_4397&SUBSYS_1609103C&REV_00\3&11 583659&0&B0"). This is relative registry path under the key "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\ ".
Go to that device`s registry key ("HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum \PCI\VEN_1002&DEV_4397&SUBSYS_1609103C&REV_00\3&11 583659&0&B0") and locate down the subkey "Device Parameters\Interrupt Management". For devices working in MSI-mode there will be subkey "Device Parameters\Interrupt Management\MessageSignaledInterruptProperties" and in that subkey there will be DWORD value "MSISupported" equals to "0x00000001". To switch device from legacy- to MSI-mode just add these subkey and value.
http://forums.guru3d.com/showthread.php?t=378044tried it myself on the GPU and Soundcard
the intel sata controller and nic's were already set in msi mode
setting msi mode on the marvell controller caused i to not function
system maybe loading slightly fast (cant say for sure)
the high dpc latency seems to be gone (still have to test it with utorrent)
more reading
http://msdn.microsoft.com/en-us/library/windows/hardware/ff548079%28v=vs.85%29.aspxhttp://msdn.microsoft.com/en-us/library/windows/hardware/ff548057%28v=vs.85%29.aspx
