Hi Kelly, On Wed, Mar 29, 2017 at 08:03:33PM +0000, Zytaruk, Kelly wrote: > I have a PCI device that is sitting behind a bridge. > > Under certain reproducible circumstances the PCI device will become > inactive. Reading the PCI config space returns all 0xFFFFFFFF. > > The bridge appears to still be functional. Reading the status from > the bridge I see a Fatal Error due to a Surprise Down event. Just to be specific, is this the "Surprise Down Error" in the AER uncorrectable error status register? "lspci -vv" probably decodes all that for you. > I am trying to figure out how to bring the device back online. > > I tried toggling the secondary bus reset bit of the Bridge Control > Register but it doesn't appear to make any difference. I still see > 0xFFFFFFFF in the device config space. Are you calling pci_reset_function() or doing this by hand? pci_reset_function() tries several different strategies, one of which is toggling the secondary bus reset bit. > I provided a pci_error_handler but the error_detected() function is > not getting called. Do you have CONFIG_PCIEAER turned on? I would naively expect AER to log something and call your error_detected() function if this error occurs (but I haven't looked at the code for a long time). > Given that these two methods are not helping me out what other > choices do I have to either reset the PCI device or hot-plug the > device from a kernel driver. Or some other method of bring the > device back to life. > > Note that I am running Linux 4.8 in dom0 on Xen (if that makes a > difference). > > Thanks, Kelly
