I'm implementing a driver for a custom pci-device which supports 32
message signaled interrupts(MSIs) (the configuration space shows this).
The device will be used on platform with a intel E5540 and tylersburg
chipset. Kernel 2.6.30.5 is used at the moment.
To enable multiple MSI i use pci_enable_msi_block(device,32); to try to
enable 32 MSIs. This function returns 1, meaning i could only register
one, and indeed when i try to register one interrupt it succeeds.
Trying to find the error i came across the following piece of code in
the kernel.
Code:
drivers/pci/msi.c:
37 #ifndef arch_setup_msi_irqs
38 int arch_setup_msi_irqs(struct pci_dev *dev, int nvec, int type)
39 {
40 struct msi_desc *entry;
41 int ret;
42
43 /*
44 * If an architecture wants to support multiple MSI, it needs to
45 * override arch_setup_msi_irqs()
46 */
47 if (type == PCI_CAP_ID_MSI && nvec > 1)
48 return 1;
49
50 list_for_each_entry(entry, &dev->msi_list, list) {
51 ret = arch_setup_msi_irq(dev, entry);
52 if (ret < 0)
53 return ret;
54 if (ret > 0)
55 return -ENOSPC;
56 }
57
58 return 0;
59 }
60 #endif
This states, it will always return 1, if the number of vectors is
greater then 1? And an architecture should override this function to
support multiple MSI? I can't really find were and if this function is
overwritten for my architecture (Intel Nehalem).
So my question is, how multiple MSIs can be acquired for my device.
NOTE: my device does not support MSI-X so this can't be used.
Kind Regards,
Rob
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