Lynx Point USB - large amount of interrupts (300k / second)

[Daniel Kolesa]

2015-01-09 23:26 GMT+00:00 Daniel Kolesa <quaker66 at gmail.com>:
> 2015-01-09 20:24 GMT+00:00 Adrian Chadd <adrian at freebsd.org>:
>> hi,
>>
>> I have a haswell desktop box at home:
>>
>> CPU: Intel(R) Core(TM) i5-4460  CPU @ 3.20GHz (3192.67-MHz K8-class CPU)
>>
>> With lynx point USB:
>
> Also Haswell here, but with H97 chipset, which means Wildcat Point
> USB. Not getting the issue.
>
>>
>> adrian at test-2:~ % dmesg | grep ehci
>> ehci0: <Intel Lynx Point USB 2.0 controller USB-B> mem
>> 0xf7f1c000-0xf7f1c3ff irq 16 at device 26.0 on pci0
>> usbus1 on ehci0
>> ehci1: <Intel Lynx Point USB 2.0 controller USB-A> mem
>> 0xf7f1b000-0xf7f1b3ff irq 23 at device 29.0 on pci0
>> usbus2 on ehci1
>>
>>
>> ehci0 at pci0:0:26:0:    class=0x0c0320 card=0x367d17aa chip=0x8c2d8086
>> rev=0x05 hdr=0x00
>>     vendor     = 'Intel Corporation'
>>     device     = 'Lynx Point USB Enhanced Host Controller'
>>     class      = serial bus
>>     subclass   = USB
>>
>> ehci1 at pci0:0:29:0:      class=0x0c0320 card=0x367d17aa chip=0x8c268086
>> rev=0x05 hdr=0x00
>>     vendor     = 'Intel Corporation'
>>     device     = 'Lynx Point USB Enhanced Host Controller'
>>     class      = serial bus
>>     subclass   = USB
>>
>>
>> and:
>>
>> xhci0: <Intel Lynx Point USB 3.0 controller> mem 0xf7f00000-0xf7f0ffff
>> irq 16 at device 20.0 on pci0
>> xhci0: 32 byte context size.
>> xhci0: Port routing mask set to 0xffffffff
>> usbus0 on xhci0
>>
>> xhci0 at pci0:0:20:0:      class=0x0c0330 card=0x367d17aa chip=0x8c318086
>> rev=0x05 hdr=0x00
>>     vendor     = 'Intel Corporation'
>>     device     = 'Lynx Point USB xHCI Host Controller'
>>     class      = serial bus
>>     subclass   = USB
>>
>> .. now, whta I'm seeing is this:
>>
>> irq16: ehci0                 21441217509      25285
>> stray irq16                            0          0
>>
>> ... systat -vmstat 1 shows the interrupt rate to be ridiculous though,
>> like 230,000 interrupts a second.
>
> The numbers it shows here are very small.
>
>>
>> Proc:                                                            Interrupts
>>   r   p   d   s   w   Csw  Trp  Sys  Int  Sof  Flt        ioflt  256k total
>>              45   6  510k   11  245 255k   16    3        cow    255k ehci0 16
>>                                                         1 zfod        ehci1 23
>>
>> .. so, what gives? :) Has anyone else seen this?
>>
>>
>>
>> -adrian
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>
> Daniel

Oops. Accidentally sent only to Adrian rather than the list. Sorry