Bug 459546

Description of problem:
My cpus are constantly at full speed because the system is servicing hardware interupts 50% of the time. modprobe -r ehci_hcd gets rid of that load

Version-Release number of selected component (if applicable):
All f9 kernels I tried

How reproducible:
100%

Steps to Reproduce:
1. run top, watch hi at ~ 50%
top - 23:37:09 up 23:05,  4 users,  load average: 0.15, 0.11, 0.15
Tasks: 156 total,   3 running, 153 sleeping,   0 stopped,   0 zombie
Cpu(s):  1.5%us,  0.7%sy,  0.0%ni, 47.7%id,  0.2%wa, 50.0%hi,  0.0%si,  0.0%st
Mem:    903804k total,   888676k used,    15128k free,    23544k buffers
Swap:  2047476k total,      128k used,  2047348k free,   482308k cached

2. modprobe -r ehci_hcd
3. watch hi go down to 0%
top - 23:37:37 up 23:06,  4 users,  load average: 0.21, 0.13, 0.15
Tasks: 156 total,   1 running, 155 sleeping,   0 stopped,   0 zombie
Cpu(s):  5.8%us,  2.0%sy,  0.0%ni, 92.1%id,  0.2%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:    903804k total,   887692k used,    16112k free,    23480k buffers
Swap:  2047476k total,      128k used,  2047348k free,   480916k cached
  
Actual results:
The system is running at full speed spending a lot of time servicing ehci_hcd interrupts

Expected results:
ehci_hcd works

Additional info:
I need noapic to boot and irqpoll if I want to use usb devices.

root@tobslap:/proc# lspci
00:00.0 RAM memory: nVidia Corporation C51 Host Bridge (rev a2)
00:00.1 RAM memory: nVidia Corporation C51 Memory Controller 0 (rev a2)
00:00.2 RAM memory: nVidia Corporation C51 Memory Controller 1 (rev a2)
00:00.3 RAM memory: nVidia Corporation C51 Memory Controller 5 (rev a2)
00:00.4 RAM memory: nVidia Corporation C51 Memory Controller 4 (rev a2)
00:00.5 RAM memory: nVidia Corporation C51 Host Bridge (rev a2)
00:00.6 RAM memory: nVidia Corporation C51 Memory Controller 3 (rev a2)
00:00.7 RAM memory: nVidia Corporation C51 Memory Controller 2 (rev a2)
00:02.0 PCI bridge: nVidia Corporation C51 PCI Express Bridge (rev a1)
00:03.0 PCI bridge: nVidia Corporation C51 PCI Express Bridge (rev a1)
00:05.0 VGA compatible controller: nVidia Corporation MCP51 PCI-X GeForce Go 6100 (rev a2)
00:09.0 RAM memory: nVidia Corporation MCP51 Host Bridge (rev a2)
00:0a.0 ISA bridge: nVidia Corporation MCP51 LPC Bridge (rev a3)
00:0a.1 SMBus: nVidia Corporation MCP51 SMBus (rev a3)
00:0a.3 Co-processor: nVidia Corporation MCP51 PMU (rev a3)
00:0b.0 USB Controller: nVidia Corporation MCP51 USB Controller (rev a3)
00:0b.1 USB Controller: nVidia Corporation MCP51 USB Controller (rev a3)
00:0d.0 IDE interface: nVidia Corporation MCP51 IDE (rev f1)
00:0e.0 IDE interface: nVidia Corporation MCP51 Serial ATA Controller (rev f1)
00:10.0 PCI bridge: nVidia Corporation MCP51 PCI Bridge (rev a2)
00:10.1 Audio device: nVidia Corporation MCP51 High Definition Audio (rev a2)
00:14.0 Bridge: nVidia Corporation MCP51 Ethernet Controller (rev a3)
00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration
00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller
00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control
03:00.0 Network controller: Broadcom Corporation BCM94311MCG wlan mini-PCI (rev 02)