On an outdated install that was updated to the current kernel (2.6.38) but still had cloog-ppl and gcc 4.5, I was able to build the module (fsc_btns, provided by the fjbtndrv 2.2.1 package in the AUR) I need for the buttons on my Fujitsu T900 tablet PC. However, with the new version of gcc (4.6), this module no longer compiles. I know it's been awhile since gcc 4.6+ was released, but I guess I was hoping this problem would fix itself, but alas, this is almost never the case.

Here is the error output:

make -C /lib/modules/2.6.38-ARCH/build M=/home/sara/abs/aur/fjbtndrv/src/fjbtndrv-2.2.1/src/linux modules
make[1]: Entering directory `/usr/src/linux-2.6.38-ARCH'
CC [M] /home/sara/abs/aur/fjbtndrv/src/fjbtndrv-2.2.1/src/linux/fsc_btns.o
In file included from include/linux/bitops.h:22:0,
from include/linux/kernel.h:17,
from /home/sara/abs/aur/fjbtndrv/src/fjbtndrv-2.2.1/src/linux/fsc_btns.c:24:
/usr/src/linux-2.6.38-ARCH/arch/x86/include/asm/bitops.h: In function ‘fscbtns_isr_do’:
/usr/src/linux-2.6.38-ARCH/arch/x86/include/asm/bitops.h:319:2: error: use of memory input without lvalue in asm operand 1 is deprecated [-Werror]
cc1: all warnings being treated as errors

make[2]: *** [/home/sara/abs/aur/fjbtndrv/src/fjbtndrv-2.2.1/src/linux/fsc_btns.o] Error 1
make[1]: *** [_module_/home/sara/abs/aur/fjbtndrv/src/fjbtndrv-2.2.1/src/linux] Error 2
make[1]: Leaving directory `/usr/src/linux-2.6.38-ARCH'
make: *** [fsc_btns.ko] Error 2

I have tried to file a bug report with the upstream developer (http://sourceforge.net/tracker/?func=detail&aid=3298087&group_id=196222&atid=956591), but have received no reply. I have categorized this issue under "Packages: Core" for I presume the bug is in gcc, not fjbtndrv, as this module builds with gcc 4.5+ < gcc 4.6 without a hassle.

By the way, the version of fjbtndrv in the AUR is outdated (I have updated the PKGBUILD on my own machine to 2.2.1, as all the PKGBUILD needs is a version bump), so if anyone wants to test this, please change the version to 2.2.1 in the PKGBUILD. Thanks.