Device (lspci) :
04:05.0 SCSI storage controller: Advanced Micro Devices, Inc. [AMD] 53c974 [PCscsi] (rev 10)

Message (dmesg) :
[    6.330158] ------------[ cut here ]------------
[    6.330192] WARNING: at kernel/irq/handle.c:146 handle_irq_event_percpu+0x110
/0x120()
[    6.330213] irq 20 handler do_DC390_Interrupt+0x0/0x954 [tmscsim] enabled int
errupts
[    6.330226] Modules linked in: tmscsim microcode fglrx(PO) vboxpci(O) vboxnet
adp(O) vboxnetflt(O) vboxdrv(O)
[    6.330249] CPU: 2 PID: 0 Comm: BFS/2 Tainted: P           O 3.10.10 #7
[    6.330256] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./870 
Extreme3, BIOS P1.60 09/14/2010
[    6.330262]  ffffffff816a4124 ffffffff81074f16 ffff8802296f4400 ffff880237d03
ef8
[    6.330272]  0000000000000000 0000000000000000 0000000000000014 ffffffff81074
f87
[    6.330282]  ffffffff81948f48 ffff880200000028 ffff880237d03f08 ffff880237d03
ec8
[    6.330290] Call Trace:
[    6.330296]  <IRQ>  [<ffffffff816a4124>] ? dump_stack+0xc/0x15
[    6.330314]  [<ffffffff81074f16>] ? warn_slowpath_common+0x56/0x80
[    6.330323]  [<ffffffff81074f87>] ? warn_slowpath_fmt+0x47/0x60
[    6.330332]  [<ffffffff816a976e>] ? _raw_spin_unlock_irq+0xe/0x40
[    6.330345]  [<ffffffffa092990f>] ? do_DC390_Interrupt+0x12f/0x954 [tmscsim]
[    6.330357]  [<ffffffffa09297e0>] ? dc390_MsgIn_0+0x520/0x520 [tmscsim]
[    6.330366]  [<ffffffff810d5690>] ? handle_irq_event_percpu+0x110/0x120
[    6.330380]  [<ffffffff810d56d7>] ? handle_irq_event+0x37/0x60
[    6.330391]  [<ffffffff810d83d0>] ? handle_fasteoi_irq+0x50/0x100
[    6.330401]  [<ffffffff810379f5>] ? handle_irq+0x15/0x20
[    6.330423]  [<ffffffff81037660>] ? do_IRQ+0x40/0xc0
[    6.330436]  [<ffffffff816a9f2a>] ? common_interrupt+0x6a/0x6a
[    6.330441]  <EOI>  [<ffffffff8103e4bd>] ? amd_e400_idle+0x3d/0x100
[    6.330458]  [<ffffffff810ab778>] ? cpu_startup_entry+0x78/0x180
[    6.330466] ---[ end trace 132bff5a0b96a11f ]---

All in all this error seems to be ignorable, the SCSI card is working just fine.