topic Re: IMX6Q Maximum MSI Signal That Can Be Generated in i.MX Processors

IMX6Q Maximum MSI Signal That Can Be Generated

segri544 — Tue, 06 Aug 2024 06:29:10 GMT

Hi,

İ am using İMX6Q, i am trying to make 32 MSI interrupt by using

ret = pci_alloc_irq_vectors(dev, 1, 32, PCI_IRQ_MSI);

ret is returned as 16. But i am expecting 32 as kernel documantation (The MSI Driver Guide HOWTO) suggests

"If a device supports both MSI-X and MSI capabilities, this API will use the
MSI-X facilities in preference to the MSI facilities. MSI-X supports any
number of interrupts between 1 and 2048. In contrast, MSI is restricted to
a maximum of 32 interrupts (and must be a power of two)."

What could be go wrong? or is max number of MSI is 16?

Re: IMX6Q Maximum MSI Signal That Can Be Generated

Zhiming_Liu — Sat, 10 Aug 2024 00:57:18 GMT

Please try to use pci_alloc_irq_vectors(dev, 32, 32, PCI_IRQ_MSI).

Best Regards
Zhiming

Re: IMX6Q Maximum MSI Signal That Can Be Generated

segri544 — Tue, 13 Aug 2024 06:27:32 GMT

I have tried this. pci_alloc_irq_vectors(dev, 32, 32, PCI_IRQ_MSI) returned as -22. thus, no MSI generated.