I'm using a self compiled vanilla kernel in LMDE distro. When I updated my kernel from 3.2.13 to 3.3.1 following error appeared: [ 6.258971] NMI: PCI system error (SERR) for reason a1 on CPU 0. [ 6.258971] Dazed and confused, but trying to continue In the previous version of kernel I would not see such an error until activating the power management via KMS. In this version of kernel error appears without activation of power management. So I think power management is activating automatically in this version of kernel. -------------------------------------------------------------------------- # dmesg | egrep "drm|radeon" [ 5.767423] [drm] Initialized drm 1.1.0 20060810 [ 6.255434] [drm] radeon kernel modesetting enabled. [ 6.255722] [drm] initializing kernel modesetting (RV515 0x1002:0x7145 0x1028:0x2003). [ 6.255742] [drm] register mmio base: 0xEFDF0000 [ 6.255744] [drm] register mmio size: 65536 [ 6.255900] [drm] Generation 2 PCI interface, using max accessible memory [ 6.255905] radeon 0000:01:00.0: VRAM: 256M 0x0000000000000000 - 0x000000000FFFFFFF (128M used) [ 6.255909] radeon 0000:01:00.0: GTT: 512M 0x0000000010000000 - 0x000000002FFFFFFF [ 6.255922] [drm] Supports vblank timestamp caching Rev 1 (10.10.2010). [ 6.255924] [drm] Driver supports precise vblank timestamp query. [ 6.255964] radeon 0000:01:00.0: irq 44 for MSI/MSI-X [ 6.255974] radeon 0000:01:00.0: radeon: using MSI. [ 6.255994] [drm] radeon: irq initialized. [ 6.257873] [drm] Detected VRAM RAM=256M, BAR=256M [ 6.257876] [drm] RAM width 64bits DDR [ 6.258024] [drm] radeon: 128M of VRAM memory ready [ 6.258026] [drm] radeon: 512M of GTT memory ready. [ 6.258049] [drm] GART: num cpu pages 131072, num gpu pages 131072 [ 6.258503] [drm] radeon: ib pool ready. [ 6.259579] [drm] radeon: 1 quad pipes, 1 z pipes initialized. [ 6.260640] [drm] PCIE GART of 512M enabled (table at 0x0000000000040000). [ 6.260658] radeon 0000:01:00.0: WB enabled [ 6.260661] [drm] fence driver on ring 0 use gpu addr 0x10000000 and cpu addr 0xff964000 [ 6.260712] [drm] Loading R500 Microcode [ 6.441299] [drm] radeon: ring at 0x0000000010001000 [ 6.441335] [drm] ring test succeeded in 10 usecs [ 6.441477] [drm] ib test succeeded in 0 usecs [ 6.441717] [drm] Radeon Display Connectors [ 6.441719] [drm] Connector 0: [ 6.441721] [drm] VGA [ 6.441723] [drm] DDC: 0x7e40 0x7e40 0x7e44 0x7e44 0x7e48 0x7e48 0x7e4c 0x7e4c [ 6.441725] [drm] Encoders: [ 6.441727] [drm] CRT1: INTERNAL_KLDSCP_DAC1 [ 6.441728] [drm] Connector 1: [ 6.441730] [drm] LVDS [ 6.441732] [drm] DDC: 0x7e30 0x7e30 0x7e34 0x7e34 0x7e38 0x7e38 0x7e3c 0x7e3c [ 6.441734] [drm] Encoders: [ 6.441735] [drm] LCD1: INTERNAL_LVTM1 [ 6.441737] [drm] Connector 2: [ 6.441738] [drm] S-video [ 6.441740] [drm] Encoders: [ 6.441741] [drm] TV1: INTERNAL_KLDSCP_DAC2 [ 6.441760] [drm] radeon: power management initialized [ 6.876927] [drm] fb mappable at 0xD00C0000 [ 6.876930] [drm] vram apper at 0xD0000000 [ 6.876931] [drm] size 4096000 [ 6.876933] [drm] fb depth is 24 [ 6.876934] [drm] pitch is 5120 [ 6.877089] fbcon: radeondrmfb (fb0) is primary device [ 7.240397] fb0: radeondrmfb frame buffer device [ 7.240399] drm: registered panic notifier [ 7.240404] [drm] Initialized radeon 2.13.0 20080528 for 0000:01:00.0 on minor 0