Are you using an ATI brand card or an ATI clone manufacturer such as Hercules etc.. ? Better yet, boot into text mode (knoppix 2) and do an lspci -n (paste the contents here, such as this
lspci -n
00:00.0 Class 0600: 1106:0601 (rev 05)
00:01.0 Class 0604: 1106:8601
00:07.0 Class 0601: 1106:0686 (rev 40)
00:07.1 Class 0101: 1106:0571 (rev 06)
00:07.2 Class 0c03: 1106:3038 (rev 1a)
00:07.3 Class 0c03: 1106:3038 (rev 1a)
00:07.4 Class 0680: 1106:3057 (rev 40)
00:07.5 Class 0401: 1106:3058 (rev 50)
00:08.0 Class 0200: 10ec:8139 (rev 10)
00:09.0 Class 0200: 10ec:8139 (rev 10)
00:0a.0 Class 0200: 10ec:8139 (rev 10)
01:00.0 Class 0300: 1023:8500 (rev 6a)
and then an lspci (like this):
lspci
00:00.0 Host bridge: VIA Technologies, Inc. VT8601 [Apollo ProMedia] (rev 05)
00:01.0 PCI bridge: VIA Technologies, Inc. VT8601 [Apollo ProMedia AGP]
00:07.0 ISA bridge: VIA Technologies, Inc. VT82C686 [Apollo Super South] (rev 40)
00:07.1 IDE interface: VIA Technologies, Inc. VT82C586B PIPC Bus Master IDE (rev 06)
00:07.2 USB Controller: VIA Technologies, Inc. USB (rev 1a)
00:07.3 USB Controller: VIA Technologies, Inc. USB (rev 1a)
00:07.4 Bridge: VIA Technologies, Inc. VT82C686 [Apollo Super ACPI] (rev 40)
00:07.5 Multimedia audio controller: VIA Technologies, Inc. VT82C686 AC97 Audio Controller (rev 50)
00:08.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10)
00:09.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10)
00:0a.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8139/8139C/8139C+ (rev 10)
01:00.0 VGA compatible controller: Trident Microsystems CyberBlade/i1 (rev 6a)
Or, ideally lspci -v (instead of lspci) it produces the irq data as well but is a lot more to copy.