Re: [PATCH 0/3] Tegra USB probe order issue fix

[Alan Stern]

On Wed, 2 Jul 2014, Tuomas Tynkkynen wrote:

> Hi all,
> 
> This series fixes a probe order issue with the Tegra EHCI driver.
> Basically, the register area of the 1st USB controller contains some
> registers that are global to all of the controllers, but that are also
> cleared when reset is asserted to the 1st controller. So if (say) the
> 3rd controller would be the first one to finish probing successfully,
> then the reset that happens during the 1st controller's probe would
> result in broken USB. So the before doing anything with the USB HW,
> we should reset the 1st controller once, and then never ever reset
> it again.

This sounds very much like the sort of thing that ought to be described 
in DT.  It is a hardware dependence, and DT exists for the purpose of 
describing the hardware.

Alan Stern

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