I followed this Howto step by step, I've tried to do it with modules or with built-in mode but my Gentoo continues hanging, for example, when I run glxgears and tvtime both together. I don't understand it!
So here you have some relevant info (ask for more if necessary please!!) :
gentoo ibai # lsmod | grep 'drm\|agp\|rad'
radeon 107040 1
drm 64148 2 radeon
radeonfb 85824 0
fb 42920 1 radeonfb
i2c_algo_bit 9096 2 bttv,radeonfb
cfbcopyarea 3840 1 radeonfb
cfbimgblt 3072 1 radeonfb
cfbfillrect 3712 1 radeonfb
i2c_core 16912 6 tuner,bttv,tveeprom,radeonfb,i2c_algo_bit,i2c_i801
intel_agp 19996 1
agpgart 28872 2 drm,intel_agp
gentoo ibai # zcat /proc/config.gz | grep MTRR
zcat: /proc/config.gz: No such file or directory
gentoo ibai # lspci | grep -i radeon
01:00.0 VGA compatible controller: ATI Technologies Inc Radeon RV100 QY [Radeon 7000/VE]
I attach my .config:
config-2.6.15-r1Hiru
Description: Binary data