Merci pour ta réaction.
Voici quelques éléments par rapport à tes questions:
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RV710/M92 [Mobility Radeon HD 4530/4570/545v] (prog-if 00 [VGA controller])
Subsystem: Toshiba America Info Systems Satellite L505-13T GPU (Mobility Radeon HD 5145)
Flags: bus master, fast devsel, latency 0, IRQ 11
Memory at c0000000 (32-bit, prefetchable) [size=256M]
I/O ports at a000 [size=256]
Memory at d6200000 (32-bit, non-prefetchable) [size=64K]
Expansion ROM at d6220000 [disabled] [size=128K]
Capabilities: <access denied>
Kernel modules: radeon
Merci.