Bug#714959: linux-image-3.2.0-4-kirkwood mdraid array fails to assemble b/c drives are not yet ready (sata_mv)
Dear Andrew Lunn,
On Wed, 26 Mar 2014 14:55:11 +0100, Andrew Lunn wrote:
> I _guess_ the real problem here is the power supply. It cannot supply
> enough power to get all the drives spinning if they all start at the
> same time. Many of the multi-bay NAS boxes have GPIO lines which are
> used to individually power up each driver in a staggered way. The QNAP
> kernel patch is doing something similar. However in its current form
> it cannot be accepted. This delay needs to be made conditional and
> only applied on hardware with a weak power supply.
>
> I will take a look at the code and see how the platform can pass a
> flag to the driver that it needs to stagger port initialization.
The Marvell LSP code also has some changes into the core ATA to
implement staggered disk spin-up. I believe they are probably visible
in the publicly visible LSP code at
https://github.com/yellowback/ubuntu-precise-armadaxp/, but I haven't
checked in detail. If you're interested, I can probably dig the LSP
patch that does that.
Thomas
--
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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