On Thu, 6 Jan 2011, Michal Marek wrote: > On Wed, Jan 05, 2011 at 11:53:33AM -0500, Alan Stern wrote: > > Up until the last kernel version or so, I could do something like: > > > > make M=drivers/usb/misc/ > > > > and the kbuild system would automatically do the right thing by > > removing the final '/'. Now it does not do so, and instead it ends up > > unnecessarily compiling bogus files like > > > > CC [M] drivers/usb/misc//usbtest.o > > It behaves the same on 2.6.36 and 2.6.35, It did change sometime within the past year. But it's not worth trying to go back and figure out exactly when. > BUT this is not what the M > variable is meant for. It should be used to build external modules, if > you want to build only a part of the kernel tree, use > > make drivers/usb/misc Okay, will do; thanks for the hint. By the way, there seems to be a lot of unnecessary build activity when a single module is changed. For example: [stern@iolanthe usb-2.6]$ make drivers/usb/gadget/ CHK include/linux/version.h CHK include/generated/utsrelease.h CALL scripts/checksyscalls.sh [stern@iolanthe usb-2.6]$ touch drivers/usb/gadget/printer.c [stern@iolanthe usb-2.6]$ make drivers/usb/gadget/ CHK include/linux/version.h CHK include/generated/utsrelease.h CALL scripts/checksyscalls.sh CC [M] drivers/usb/gadget/printer.o LD [M] drivers/usb/gadget/g_zero.o LD [M] drivers/usb/gadget/g_ether.o LD [M] drivers/usb/gadget/gadgetfs.o LD [M] drivers/usb/gadget/g_file_storage.o LD [M] drivers/usb/gadget/g_serial.o LD [M] drivers/usb/gadget/g_printer.o LD [M] drivers/usb/gadget/g_cdc.o It's perfectly understandable that printer.o and g_printer.o need to be rebuilt. But why all those other "LD [M]" lines? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
