On Tue, May 31, 2016 at 06:41:24PM +0000, Rob Groner wrote:
I am trying to load a driver for an Exar serial chip, but that chip is gobbled up by the 8250 driver on boot.
Why does the in-kernel driver not support this chip? Do you have a pointer to the Exar source anywhere?
So, I use the “unbind” command in /sys/bus/pci/ drivers/serial to remove the device from the clutches of 8250. Based on cobbled together google searches, I use the following to unbind it (assuming the address in /sys/bus/pci/drivers/serial is 0000:04:00.0.
That's a huge hammer, are you sure that's the best way to do this? Why not just add your device to a blacklist in the 8250 driver?
So, as near as I can tell, when the Exar driver is inserted, an interrupt flood occurs, and the Exar driver (the only interrupt handler on that IRQ) does not respond to any of them. I put in some debug code and verified that the Exar interrupt handler is called… but the handler just returns with an IRQ_NONE value.
Sounds like a bug in the Exar driver, why isn't it handling the interrupt properly? thanks, greg k-h