Re: ahci_start_engine compliance with AHCI spec

[Tejun Heo]

Hello,

On Tue, Aug 02, 2011 at 05:06:13PM -0700, Brian Norris wrote:
> Can DRQ be set from 0->1 without a software-initiated action? I didn't
> think it was directly tied to PHY events, and so we can fairly well
> predict that it will remain 0.

Sure it can.  It's updated by Register D2H FISes sent by the device.
It can change after a PHY event; otherwise, I don't think it would get
set during init without any command in flight, right?

> Yes, I believe the hardware designers know how buggy this is...but
> it's still worth some effort to fix the software as well as possible
> for current hardware behavior.

Yeap, sure, let's get it working for majority of cases.  I just wanted
to point out that the hardware eventually needs to be fixed.

Thanks.

-- 
tejun
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