View previous topic :: View next topic |
Author |
Message |
Myu Apprentice


Joined: 22 Oct 2014 Posts: 164 Location: Belgium
|
Posted: Thu Feb 04, 2016 6:22 pm Post subject: System generate IRQ's by itself ? |
|
|
Hello Gentooers,
I've a rather small and not really pressing issue but I would like to get to the bottom of it if I can. It might be related to my hardware or to an ( hopefully ) good surnatural spirit
My system is generating IRQ by itself ... (even without any HID devices like mouse or keyboard plugged )
I can see it in multiples ways :
If I'm on a terminal in the middle of an output, it scrolls down often after a few seconds ( 5 to 20 )
If there's xscreensaver active, I often get the username / password prompt for no reasons
If I'm watching a fullscreen video on youtube for instance, the controls are reapparing from time to time.
Could there be a way to watch an output of HID IRQ's ? Or all IRQ's even ?
Have a nice evening ! _________________ Gentoo stable with bits of ~amd64 // Xfce 4.13 + Compiz Reloaded. |
|
Back to top |
|
 |
NeddySeagoon Administrator


Joined: 05 Jul 2003 Posts: 44171 Location: 56N 3W
|
Posted: Thu Feb 04, 2016 8:36 pm Post subject: |
|
|
Myu,
This is possibly the result of having PS/2 mouse and keyboard support enabled but no devices connected.
PS/2 is actually a simplified serial port. With no devices connected, the wires act like antenna and pick up electrical noise.
Every now and again, this electrical noise generates a valid character and a IRQ is raised.
I have not seen it a lot.
USB data is organised into packets. Its much harder to generate a random but valid USB packet, so it tends not to happen with USB. _________________ Regards,
NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
|
Back to top |
|
 |
Myu Apprentice


Joined: 22 Oct 2014 Posts: 164 Location: Belgium
|
Posted: Thu Feb 04, 2016 8:54 pm Post subject: |
|
|
Hi NeddySeagoon,
This is an interesting (and unexpected) thought to say the least !
Indeed I do have a PS/2 port and support enabled in my current kernel. I'll see if disabling them does any good.
Thank you for your kind answer, I'll keep you posted  _________________ Gentoo stable with bits of ~amd64 // Xfce 4.13 + Compiz Reloaded. |
|
Back to top |
|
 |
NeddySeagoon Administrator


Joined: 05 Jul 2003 Posts: 44171 Location: 56N 3W
|
Posted: Thu Feb 04, 2016 8:58 pm Post subject: |
|
|
Myu,
Another possible fix is to make fake PS/2 devices that do nothing more than connect the data line to 0v. _________________ Regards,
NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
|
Back to top |
|
 |
Myu Apprentice


Joined: 22 Oct 2014 Posts: 164 Location: Belgium
|
Posted: Thu Feb 04, 2016 9:12 pm Post subject: |
|
|
Neddy,
So with PS/2 disabled on the BIOS and PS/2 support removed from the kernel, it still happens quite often.
Your second idea is interesting as well, although I wonder if it would have any impact on a BIOS-disabled PS/2 port.
I'll see if I can tinker with a PS2 to usb adapter to make something like you've proposed. _________________ Gentoo stable with bits of ~amd64 // Xfce 4.13 + Compiz Reloaded. |
|
Back to top |
|
 |
NeddySeagoon Administrator


Joined: 05 Jul 2003 Posts: 44171 Location: 56N 3W
|
Posted: Thu Feb 04, 2016 9:18 pm Post subject: |
|
|
Myu,
Look in /proc/interrupts
Code: | CPU0 CPU1 CPU2 CPU3 CPU4 CPU5
0: 64 36 87 517 10282 748776 IO-APIC 2-edge timer
1: 0 0 0 0 0 2 IO-APIC 1-edge i8042 |
IRQ 1 is the i8042 PS/2 controller.
I have a total of 2 i8042 IRQs in a few hours. I do not have any PS/2 devices connected. _________________ Regards,
NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
|
Back to top |
|
 |
Myu Apprentice


Joined: 22 Oct 2014 Posts: 164 Location: Belgium
|
Posted: Thu Feb 04, 2016 9:27 pm Post subject: |
|
|
Neddy,
I see ! So it's almost quite common.
On my end, I do not have a i8042 IRQ (after the changes of course) :
Code: | 0: 122 0 0 0 IO-APIC-edge timer
8: 21 0 0 0 IO-APIC-edge rtc0
9: 0 0 0 0 IO-APIC-fasteoi acpi
16: 110667 0 0 0 IO-APIC 16-fasteoi ehci_hcd:usb1
... |
_________________ Gentoo stable with bits of ~amd64 // Xfce 4.13 + Compiz Reloaded. |
|
Back to top |
|
 |
NeddySeagoon Administrator


Joined: 05 Jul 2003 Posts: 44171 Location: 56N 3W
|
Posted: Thu Feb 04, 2016 9:36 pm Post subject: |
|
|
Myu,
Well, if you no longer have a i8042 entry, its not PS/2 related.
You don't have IRQ3 and 4 either, which are the real serial ports fitted to older PCs. _________________ Regards,
NeddySeagoon
Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail. |
|
Back to top |
|
 |
|