ada(4) and ahci(4) quirk printing

Steven Hartland killing at multiplay.co.uk
Tue Apr 23 12:20:11 UTC 2013


----- Original Message ----- 
From: "Jeremy Chadwick" <jdc at koitsu.org>
>> Wouldn't camcontrol be a better place for this?
> 
> 1) Not possible at this time -- the ADA_Q_* quirks are not exported to
> userland (i.e. /usr/include), only the kernel.  camcontrol's source only
> relies on things in userland.

Thats not an issue which is hard to resolve.

> 2) Assuming #1 is addressed: where would it go?  You can't put it under
> "camcontrol identify" because all (I repeat: ALL) that information comes
> from ATA IDENTIFY and thus would be extremely misleading.  (Same goes
> for SCSI's INQUIRY stuff).  Which leads me to...

A new quirks option makes the most sence which could be used not only by
disks but other areas too.
> 
> 3) I'm never thrilled about adding new commands to camcontrol given
> how enormous that thing is to begin with.  :-)  I also imagine something
> like "camcontrol quirks" might lead people to think it lets you adjust
> quirks in real-time (nope -- read-only, tunable-only).  And that leads
> me to...

Again depends how its implemented if we fix / improve the CCB situation
this could be handled quite elegently with even with the possiblibly of
changing on the fly. I know scottl has some thoughts on this.

> 4) camcontrol wouldn't address the need/interest for ahci(4) quirks to
> be made available.

Why?

> 
> All of these things combined do lead me to believe sysctl is the better
> place for this.
> 
> P.S. -- I just noticed that our USB layer prints device quirks
> regardless of bootverbose -- instead it's based on kernel option
> USB_DEBUG, which is enabled in GENERIC.  Hooray for inconsistency.

Personally while I like a relatively clean output I think its important
that the information is available when needed, and that shouldn't require
a reboot.

So if this info isn't available else where I would say adding to standard
output (not verbose only)is a good option especially since its often as
important to know a quirk is in place or for 4K not in place as say
transfer speed / data spec e.g. SATA 2.x.

    Regards
    Steve


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