Hi Greg,

After merging the tty tree, today's linux-next build (powerpc
ppc64_defconfig) failed like this:


drivers/built-in.o: In function `.serial8250_stop_tx':
8250_core.c:(.text+0xda1f4): undefined reference to `.__xchg_called_with_bad_pointer'
drivers/built-in.o: In function `.serial8250_tx_chars':
(.text+0xda42c): undefined reference to `.__xchg_called_with_bad_pointer'
drivers/built-in.o: In function `.serial8250_start_tx':
8250_core.c:(.text+0xda630): undefined reference to `.__xchg_called_with_bad_pointer'

Caused by commit d74d5d1b7288 ("tty: serial: 8250_core: add run time
pm").  xchg is called with &p->rpm_tx_active and that is an unsigned
char.  PowerPC (at least) only allows xchg with objects 4 (or 8 on 64
bit) bytes long.

I have used the version of the tty tree from next-20140926 for today.
-- 
Cheers,
Stephen Rothwell                    sfr@canb.auug.org.au