Legacy features in PCI Express devices
slash.tmp at free.fr
Mon Mar 13 09:10:57 PDT 2017
There are two revisions of our PCI Express controller.
Rev 1 did not support the following features:
1) legacy PCI interrupt delivery (INTx signals)
2) I/O address space
Internally, someone stated that such missing support would prevent
some PCIe cards from working with our controller.
Are there really modern PCIe cards that require 1) and/or 2)
Can someone provide examples of such cards, so that I may test them
on both revisions?
I was told to check ath9k-based cards. Any other examples?
Looking around, I came across this thread:
"i.MX6 PCIe: Fix imx6_pcie_deassert_core_reset() polarity"
IIUC, although some PCIe boards do support MSI, the driver might not
put in the work to use that infrastructure, and instead reverts to
legacy interrupts. (So it is a SW issue, in a sense.)
More information about the linux-arm-kernel