Re: Loud "pop" coming from hard drive on reboot

[Stephen Clark <Stephen.Clark@seclark.us>]

Alan Cox wrote:

>>Thought about that and querying power state before doing shutdown 
>>sequence but things get somewhat ugly because shutdown sequence is 
>>driven from sd->shutdown().  We'll have to snoop both sync and shutdown 
>>commands and check whether the system is shutting down.  Also, I felt 
>>very uneasy about faking successful completion to SYNCHRONIZE_CACHE.
>>    
>>
>
>If you see a synchronize cache succeed and you then see the drive
>shutdown succeed then you know that a sync cache can be faked as ok
>safely. Any other command in between or after and it doesn't get faked
>
>This seems pretty easy to deal with at command issue.
>
>  
>
>>I dunno.  It's already too late for 2.6.21.  I was hoping we could get 
>>distros to update shutdown utilities in not-too-distant future but I 
>>have no experience with that.  Is that just a wishful thinking?
>>    
>>
>
>Probably not, but it will take a year or so and throughout this time
>period everyone with the wrong combination of shutdown and kernel (which
>will be a lot of people who compile their own kernels) are going to have
>problems caused by what is a very obscure piece of libata internal
>behaviour they'll never even know about.
>
>  
>
So this is the pop I hear on my new laptop that is using 
libata=combined_mode
 when I shut my system down. I didn't get the pop with the same disk 
drive in an older
 laptop that was only ide. It sounds like a relay closing or opening, 
but is really my
drive head doing an emergency retract/park?

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