Determine DMA channels in use?

Dear All,

I am just wondering if there is any way to check the DMA Channels that are allocated during runtime on a QNX 4.25 machine. Something like sin irq would be fine but I can’t find anything in that direction…

Any information will be appreciated 8)

Jens Schirmer

No it’s not possible.

Hum not entirely true, you can use show_pci to check which PCI devices have request DMA channel ( master card) but that’ about it.

Hi Mario,

thanks for your quick response. Unfortunately, we are using a legacy ISA Card, so it won’t show up on the show_pci command



Check out rsrcdbmgr_query(). Of course, it is a cooperative system, so as long as the ISA driver used rsrcdbmgr_attach() to reserve the DMA resource you’re in luck…


Hi Rennie,

nope, the ISA driver does not use rsrcdbmgr_attach(), so this not an option for us. I assume this would be QNX 6.x thing? We’re using 4.25…

But thanks for the hint, gonna have to migrate anyway some day :slight_smile: