On Tue, Nov 29, 2011 at 10:54 AM, Michael S. Tsirkin <mst@xxxxxxxxxx> wrote: > I think panic on iomap is there just for debugging. > If we return NULL instead, the generic pci_iomap will > DTRT so we don't need to roll our own. Just to be explicit about what "doing the right thing" means, here's what I think is changing (I think the new behavior is OK, but it *is* different): Old behavior: Caller calls pci_iomap(), which panics in ioport_map(). New behavior: Caller calls pci_iomap(), ioport_map() returns NULL, pci_iomap() returns NULL (failure), caller may check for failure. If caller does not check for failure and passes the NULL to ioread()/iowrite(), we WARN in bad_io_access(). > static inline void __iomem *ioport_map(unsigned long port, unsigned int len) > { > - return (void __iomem *) ioport_panic(); > + pr_info("Trying to map an IO resource - it does not exit on tile.\n"); > + return NULL; s/exit/exist/ Since we only expect to see this message during debugging, maybe it could be more informative, e.g., use dump_stack() to identify the offending driver? I don't think either the "Trying to map" message or the "Bad IO access" message is enough to actually make progress in debugging. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html