From mboxrd@z Thu Jan 1 00:00:00 1970 From: greg@kroah.com (Greg KH) Date: Tue, 31 May 2016 13:14:24 -0700 Subject: Trying to debug interrupt flood after unbind In-Reply-To: References: Message-ID: <20160531201424.GA23248@kroah.com> To: kernelnewbies@lists.kernelnewbies.org List-Id: kernelnewbies.lists.kernelnewbies.org 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