I have several devices which can resize their BARs at runtime (e.g. an FPGA which, after being programmed, will add new BARs and/or resize one of the existing BARs). However, I have been unable to get the kernel to resize the resources allocated to the device at run time. For example, this is a typical situation: System comes up, enumerates device. Device currently exposes only BAR0, at some size (say 64k) System programs device via BAR0. Device changes its PCI configuration space header to indicate that BAR1 is now valid, for a size of 128k System code calls the kernel to rescan (e.g. pci_scan_slot()). In this case the kernel will sometimes allocate resources for BAR1. However, consider this case: System comes up, enumerates device. Device currently exposes BAR0, at some size (say 64k), and BAR1, at some other size (say 128k) System programs device via BAR0. Device changes its PCI configuration space header to indicate that BAR1 now 256k System code calls the kernel to rescan (e.g. pci_scan_slot()). In this case I cannot get the kernel to resize the resources/sysfs attributes/etc. of BAR1 to take the new size. I've tried releasing the resources. If I shut the PCI device down, then my driver gets turned off (not good). Is there any way to tell the kernel "things have changed on the hardware, rescan, but DON'T destroy the device driver - it knows how to deal with this!" I realize that in some situations it may not be possible to reallocate resources (e.g. upstream bridges don't have the space) - assume for the moment that's not a problem. -- 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
