Windows: Line-Based vs. Message Signaled-Based Interrupts. MSI tool.

X2APIC architecture guide

 

The latest cards support it by default.

 

Can I safely disable MSI Mode on my M2 NVME which has the OS installed?

Sorry if this has been asked before, I couldn't find an answer.

 

no

 

Why? It does not work in legacy mode?

 

many nvme controllers don't actually support IntX emulation or are significantly impared by using it due to the lack of Interrupt aggregation.

So i can't reply with "Yes" to the question of it being safe without knowing the devices controller, history of issues, etc.

 

Ok I guess I won't touch it for now.

But is it normal that every device shares IRQ 16 after disabling MSI Mode? GPU, LAN, Audio, IMEI, USB ... seems a bit weird to me.

 

Why disable it though?

 

Yes, your mainboard manual has a picture of the physical irq's that are used.

Common X2Apic platforms have 2 independant irq providers that permits usage of the same IRQ without the same levels of issues (as well as irq steering).

all of these parts are natively all msi's though so you've just turned on emulation rather than turned off msi (excluding usb 2.x, which is an irq signalled controller)

 

If Windows is working without issues with IRQ 16 shared among all those devices then it is normal.
It is not normal from performance point of view, because IRQ sharing adds latencies.

 

I'm using Windows 10 20H2.

SATA interrupt priority is set to high by default, wich I can understand.
Ethernet is also but I'm not so sure about this one. Wouldn't this deteriorate other devices while playing online since it is always transmiting?
This makes more sense for servers but not for desktop users.

Also, the Interrupt Affinity Policy Tool shows that SATA is set to 'SpreadMessagesAcrossAllProcessors' but it is not doing anything since SATA doesn't support MSI-X.
Wouldn't it be better to set 'AllProcessorsInMachine' ?
Anyway to check if affinity is working?
All interrupts go to cpu 0. What about setting ethernet interrupts to the last cpu?

 

I have disabled stuff just for testing purposes. I feel like disabling most of the MSI Modes makes mouse feel more natural, but can't say much because I am still testing.

How do I avoid IRQ sharing other than MSI Mode, are some mainboards better in that way? How can I know without buying different kind of motherboards?

 

In old days you could change IRQ number in device`s properties dialog. Nowadays you can`t.

 

Hi Folks,

short Questions, when i use the MSI Tool there ist HD Audio Controller with this Subsys

PCI\VEN_1022&DEV_1487&SUBSYS_87C51043&REV_00\4&231A312E&0&0441

but in Device Manager there ist Realtek(R) Audio with Subsys

HDAUDIO\FUNC_01&VEN_10EC&DEV_1168&SUBSYS_104387C5&REV_1001

so when i change the MSI Setting for HDA Controller, has this an Effect or not? Same Root Device?



The Problem is, that i have a Audio Delay that is very annoying, especially in Games.

 

"VEN_1022" is AMD. I assume that this audio controller is on videocard. You can check that by comparing "Location: PCI-Bus 12, Gerat 0, Funktion 4" of audio controller with location of Radeon (it should be like "Location: PCI-Bus 12, Gerat 0, Funktion 0" - same PCI-Bus and Gerat but different Funktion).

PS You can double-click on any device and tool should bring its registry key.

 

Your´re right but where is the Realtek Driver? It´s not there...

i found it in Registry but there are no MSI Parameters in there


I must disable all audio enhancements , than it´s not delayed Audio. But that could not be the Solution, cause i use sonic Studio and Nahimic a lot.

 

Here is hardware ID of my Realtek audio controller: HDAUDIO\FUNC_01&VEN_10EC&DEV_1168&SUBSYS_10438733&REV_1000
And instance ID: HDAUDIO\FUNC_01&VEN_10EC&DEV_1168&SUBSYS_10438733&REV_1000\4&87D3799&0&0001

Just launch MSI tool, find instance with "HDAUDIO\FUNC_01&VEN_10EC&DEV_1168" and switch it to MSI mode (that will add MSI parameters to registry), reboot.

PS It can be that Realtek device is not in MSI tool, because it does not live under the "PCI" registry key. I do not see it on my rig, but instead I see this:

Code:

Device PNP properties
    Display name    : High Definition Audio Controller
    Manufacturer    : Microsoft
    Location    : PCI bus 0, device 31, function 3
    Instance ID    : PCI\VEN_8086&DEV_A2F0&SUBSYS_87331043&REV_00\3&11583659&0&FB
    PDO name    : \Device\NTPNP_PCI0113
    Driver version    : 10.0.19041.1
    Driver inf-path    : hdaudbus.inf
    Driver provider    : Microsoft
    Driver rank    : 16719878
Device PCI properties
    PCI device type    : PciConventional
    Interrupt modes    : LineBased, Msi
    Max MSI limit    : 1

It pretends to be an Intel device.

 

I am on a Ryzen System and i found it under HDAUDIO in Registry. The Problem there are no Interrupt Policies. So i can´t change it right? In MSI Tool is no Entry for this Device.

 

What is written in details of "High Definition Audio Bus" (in MSI tool)?

(You can select the text and copy-and-paste it here.)

 

I have two ,

this:




and this: