Problema Mobility Radeon 7500 su linux

[bluehorse]

Ciao, qualcuno ha provato a installare Ubuntu su un portatile con radeon 7500M? Dopo l'installazione ottengo i seguenti errori e l'interfaccia grafica si freezza:

[drm:radeon_cp_start] *ERROR*
radeon_cp_start called without lock held, held 0 owner f726bc80 f68f6840
Dec 6 10:24:31 kernel: [ 186.138968] [drm:radeon_cp_idle] *ERROR*
radeon_cp_idle called without lock held, held 0 owner f726bc80 f68f6840
Dec 6 10:24:31 kernel: [ 186.139214] [drm:radeon_cp_reset] *ERROR*
radeon_cp_reset called without lock held, held 0 owner f726bc80 f68f6840
Dec 6 10:24:31 kernel: [ 186.139408] [drm:radeon_cp_start] *ERROR*
radeon_cp_start called without lock held, held 0 owner f726bc80 f68f6840
Dec 6 10:24:31 kernel: [ 186.139601] [drm:radeon_cp_idle] *ERROR*
radeon_cp_idle called without lock held, held 0 owner f726bc80 f68f6840
Dec 6 10:24:31 kernel: [ 186.139866] [drm:radeon_cp_reset] *ERROR*
radeon_cp_reset called without lock held, held 0 owner f726bc80 f68f6840
Dec 6 10:24:31 kernel: [ 186.140072] [drm:radeon_cp_start] *ERROR*
radeon_cp_start called without lock held, held 0 owner f726bc80 f68f6840
Dec 6 10:24:31 kernel: [ 186.140467] [drm:radeon_cp_idle]

Devo installare un altro driver? Qualcuno ha qualche suggerimento?

Grazie