Need help on understanding hardware detection

[Tao Jiang (姜涛)]

Saqlain: 
    Thanks for your reply. 
    The article really opened my eyes. 
    But in that article wrote as  
    1.  " Linux kernel constantly scans all your computer bus’es  for any changes and new hardware. Once any change on any bus is detected magic begins " 
    And in the comments at the bottom,  
    2.  "a bus controller notifies the CPU through an interrupt which allows the kernel to query the controller back for information" 
    So my question is which one is right? 
    And can you show me more details on Linux kernel's implementation about "constantly scans" or "notifies the CPU through an interrupt"? 
 
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Tao Jiang (姜涛) 
2013-08-20 
 
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发件人：Saqlain Abbas <saqlain.abbas.7 at gmail.com> 
发送日期：2013-08-19 19:53 
收件人：Tao Jiang (姜涛) 
抄送：kernelnewbies 
主题：Re: Need help on understanding hardware detection 
 
have a look at http://blogas.sysadmin.lt/?p=141 will give you a nice idea... 
 
Cheers, 
Saqlain. 
 
 
On Mon, Aug 19, 2013 at 4:47 PM, Tao Jiang (姜涛) <jiangtao.jit at gmail.com>wrote: 
 
> Hi All: 
>         I did some search on "how does linux kernel detect hardware?" and 
> got what udev is. 
>         I konw Linux kernel will send a netlink message to udevd. 
>         But I still do not understand how the kernel can decide to send a 
> netlink message. 
>         What happend before the netlink message? 
>         Take an usb stick for example, what will happen and what the 
> kernel do from the very beginning of it been plugged in? 
>         Thank you for advance. Any references will be appreciated. 
> 
> -------------- 
> Tao Jiang (姜涛) 
> 2013-08-19 
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> 
 
 
 
--  
Kind Regards, 
Saqlain Abbas.