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

[Tejun Heo <htejun@gmail.com>]

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.

Yeah, right.  I guess I'm too anal about SYNCHRONIZE_CACHE.

>> 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.

Okay, will do another round of the patch.

Thanks.

-- 
tejun