On Tue, 18 Sep 2007 01:18:41 PDT, Andrew Morton said:
quoted text
> 
> ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.23-rc6/2.6.23-rc6-mm...

% uname -a
Linux turing-police.cc.vt.edu 2.6.23-rc6-mm1 #1 SMP PREEMPT Tue Sep 18 12:32:13 EDT 2007 x86_64 x86_64 x86_64 GNU/Linux
% uptime
 15:11:48 up 36 min,  1 user,  load average: 0.05, 0.11, 0.09

Had a few issues, all self-inflicted (the biggie was 2 iptables modules that
needed fixing for the net namespace changes in git-net.patch - stuck an
&init_net in the right 2 places, a new #include line, and all was good).

I *did* have an odd issue with an out-of-tree GPL driver for a webcam.
(It's from http://mxhaard.free.fr/ if anybody cares).

The Makefile does this:

make -C /lib/modules/`uname -r`/build SUBDIRS=/home/valdis/src/gspcav1-20070508 CC=cc modules

and has this sort of stuff in it:

DEFINES   += -DGSPCA_ENABLE_DEBUG
DEFINES   += -DCONFIG_USB_GSPCA_MODULE=1 -DMODULE -D__KERNEL__
DEFINES   += -DVID_HARDWARE_GSPCA=0xFF -DGSPCA_VERSION=\"$(VERSION)\"

In -rc4-mm1, $DEFINES got added to the compile command - in -rc6-mm1, I
had to namually add a 'CFLAGS += $(DEFINES)' or GSPCA_VERSION came up undefined.

The actual problematic code in the Makefile:

-- begin Makefile snippet
ifneq ($(KERNELRELEASE),)   # We were called by kbuild
CFLAGS += $(DEFINES)
obj-m += gspca.o
gspca-objs := gspca_core.o decoder/gspcadecoder.o

else   # We were called from command line

KERNEL_VERSION = `uname -r`
KERNELDIR := /lib/modules/$(KERNEL_VERSION)/build
PWD  := $(shell pwd)
MODULE_INSTALLDIR = /lib/modules/$(KERNEL_VERSION)/kernel/drivers/usb/media/
MODULE_INSTALLDIR2 = /lib/modules/$(KERNEL_VERSION)/kernel/drivers/media/video/

default:
        $(MAKE) -C $(KERNELDIR) SUBDIRS=$(PWD) CC=$(CC) modules

install:
        mkdir -p $(MODULE_INSTALLDIR)
        rm -f $(MODULE_INSTALLDIR)spca5xx.ko
        rm -f $(MODULE_INSTALLDIR2)gspca.ko
        install -c -m 0644 gspca.ko $(MODULE_INSTALLDIR)
        /sbin/depmod -ae

uninstall:
        rm -f $(MODULE_INSTALLDIR)gspca.ko
        /sbin/depmod -aq

endif
--- end Makefile snippet

The Make definitely falls into the 'else' part (verified by adding an 'echo'
to the default: target).  Adding the CFLAGS += to the else, or moving the line
above the if, makes it work.