We are using Xenomai 3.1.2 on kernel 4.19.229, X86 CPU We have a (Moxa CP-104ul) serial card on an isolated PCI bus interrupt 17. lspci -v confirms that the serial card is isolated and that no other peripheral uses this interrupt.
We have the 16550A serial driver loaded, and an external serial device trying to initiate a serial connection, but no interrupts are being generated. The interrupt counter in /proc/xenomai/irq stay at 0. [user@device~]$ cat /proc/xenomai/irq IRQ CPU0 CPU1 CPU2 CPU3 17: 0 0 0 0 rtser2 rtser3 rtser4 rtser5 As an experiment: if we enable the Azalia sound chip in the BIOS, and load its Alsa sound driver, the Serial card will then share IRQ 17 with that sound chip, and then the serial card works. The serial interrupt counter is incrementing in /proc/xenomai/irq and our serial peripheral can utilize the serial port OK. We don't want the sound driver enabled, but this test indicates that 16550A somehow failed to enable its interrupt, whereas the sound driver succeeded in doing so. How can we check a PIC, etc. to verify that the serial interrupt is truly enabled when the 16550A driver is loaded alone?
