Re: Cinergy T2 stopped working with kernel 2.6.30

[emagick@magic.ms]

The more I look into this problem the stranger it becomes. I've compiled
the kernel for different CPUs:

                  |    mplayer               mythtv
-----------------+--------------------------------------------
CONFIG_M486      |    works                 works
CONFIG_M586      |    works                 cannot tune
CONFIG_MCORE2    |    cannot tune           cannot tune

These results are for my Atom N270 board. On my Core2 board, the Cinergy T2 works
all the time.

By applying -march=i486 and -march=i586 to individual source files, I found
out that dvb_frontend.c is the culprit.

By editing the assembly output for dvb_frontend.c, I found out that only
dvb_frontend_swzigzag_autotune() needs to be compiled with CONFIG_M486 to
make the Cinergy T2 work, everything else can be compiled with CONFIG_M586.

Both compiled versions of dvb_frontend_swzigzag_autotune() look OK (but I
haven't yet strictly verified the assembly code). Anyway, nothing in that
code should make a difference on N270 vs. Core, except for timing. Adding
NOPs doesn't seem to make a difference.

Any ideas? Could this be a CPU bug?