Currently I have both ATI HD 6470M and Intel i5(Intel Graphics HD 3000) on my laptop. Version of my kernel is 2.6.38(so the Intel Graphics chip is somewhat working). I did not install the close-source ATI graphic card driver.

Every time I try to play videos, X will just gone dead, but the audio part was always still working. I also tried to use xv and SDL as the video output, but they make no difference.

I tried running some simple SDL programs. It worked, but starts up extremely slow.

Here is some info that may help:
wecing@D5:~$ glxinfo
name of display: :0.0
Unrecognized deviceID 116
X Error of failed request: BadAlloc (insufficient resources for operation)
Major opcode of failed request: 154 (GLX)
Minor opcode of failed request: 3 (X_GLXCreateContext)
Serial number of failed request: 21
Current serial number in output stream: 24

wecing@D5:~$ sudo lshw -C video
*-display
description: VGA compatible controller
product: NI Seymour [AMD Radeon HD 6470M]
vendor: ATI Technologies Inc
physical id: 0
bus info: pci@0000:01:00.0
version: 00
width: 64 bits
clock: 33MHz
capabilities: pm pciexpress msi vga_controller bus_master cap_list rom
configuration: driver=radeon latency=0
resources: irq:51 memory:a0000000-afffffff memory:c6500000-c651ffff ioport:5000(size=256) memory:c6520000-c653ffff
*-display
description: VGA compatible controller
product: Sandy Bridge Integrated Graphics Controller
vendor: Intel Corporation
physical id: 2
bus info: pci@0000:00:02.0
version: 09
width: 64 bits
clock: 33MHz
capabilities: msi pm vga_controller bus_master cap_list rom
configuration: driver=i915 latency=0
resources: irq:48 memory:c0000000-c03fffff memory:b0000000-bfffffff ioport:6000(size=64)

wecing@D5:~$ lsmod | grep radeon
radeon 717227 0
ttm 52155 1 radeon
drm_kms_helper 26893 2 radeon,i915
drm 165567 5 radeon,i915,ttm,drm_kms_helper
i2c_algo_bit 12834 2 radeon,i915
power_supply 13475 3 radeon,battery,ac
i2c_core 23725 7 radeon,videodev,i915,i2c_i801,drm_kms_helper,drm,i 2c_algo_bit