Hi there

We have an x86 routerpc with 5 wireless cards. 4 of them work fine, but when we enable the 5th one and it connects/authenticates with the client side, the entire PC crashes.

I've searched everywhere for an answer, and the only thing I can see that could cause it is that the 5th card shares an IRQ with another one. So when it's disabled it's fine, but when I switch it on it fails.

My question is this: could this be causing my issue? If so, is there any way to force IRQ selections within RouterOS? I did disable all unnecessary items in the BIOS such as USB and audio to free up as many IRQs as possible.

I have tried with RouterOS 4.10, 5beta2, 5beta4 and 5beta5, and all of them assign 2 cards to IRQ 22.

Thanks

Hi, what wireless cards and mPCI adapter you use ( RB11,RB14 or RB18 )? How much Amps@5V you have on PCI bus. I am not think that is IRQ related problem.

we use Rb14 and have 25watt for each pci slot

1st pci slot 1 x rb14 = 2 x r5h and 2 x r52Hn no problems (1 x r5h is on irq22)

2nd pci slot 1 x rb14 = 1 x r52Hn (irq22)

2xR5H= 3,2A ; 2xR52Hn=4,24A Total= 7,44A x 5V = 37,2W You overload your PC. Else check LDO on each RB14, some old batch have 3A LDO that mean 1,5A for each mPCI. Try reduce TX power on all wireless cards to few dBm and test again.

2xR5H= 3,2A ; 2xR52Hn=4,24A Total= 7,44A x 5V = 37,2W You overload your PC. Else check LDO on each RB14, some old batch have 3A LDO that mean 1,5A for each mPCI. Try reduce TX power on all wireless cards to few dBm and test again.

I believe your calculation to be faulty. Regardless of voltage, an R5H can draw a maximum of 5W each, while an R52Hn draws 7W each on dual chain. I am using both cards on single chain, therefore each card would draw no more than 4W. Add this together and you get 18W total, assumin all cards are running on MAX power, which they are not. And this is well within specs of a PCI slot (25W total).

Furthermore, the 5th card (the one that causes the crash) in on the second RB14 in another PCI slot by itself, so it has more than enough power. Even if I disable all 4 the other cards, this one still crashes.

This leads me to believe it has more to do with IRQ sharing conflicts than lack of power.

Have a look at the PCI Interrupt Request Routing table in your mainbords user manual. The IRQ (interrupt request line) are hardware lines over which devices can send interrupt signals to the microprocessor.

Ok, may be your problem is not power related but your calculation ir wrong. OK take 18W @ 3,3V = 5,45A RB14 use LDO and 5V like power source. 5,45 x 5V = 27,25W. Try change RB14 , R52Hn and PCI slot may be it's broken.