[U-Boot] [PATCH] usb: ehci-omap: Don't softreset USB High-speed Host (UHH) Module

[Stefan Roese]

On 07/22/2013 10:14 AM, Roger Quadros wrote:
> Fixes NFS root problems with Beagle (3530 ES1.0) when used with
> external USB-ethernet adapter and "USB start" command used within
> u-boot.
> 
> Soft resetting the UHH module causes instability issues on
> all OMAPs so we just avoid it.
> 
> See OMAP36xx Errata
>   i571: USB host EHCI may stall when entering smart-standby mode
>   i660: USBHOST Configured In Smart-Idle Can Lead To a Deadlock
> 
> On OMAP4/5, soft-resetting the UHH module can put it into
> Smart-Idle mode and lead to a deadlock.
> 
> On OMAP3 this doesn't seem to be the case but still instabilities
> are observed on beagle (3530 ES1.0) if soft-reset is used.
>  e.g. NFS root failures with Linux kernel.
> 
> Signed-off-by: Roger Quadros <rogerq at ti.com>

Thanks a lot for fixing this. With this patch, beagleboard is able to
boot into an NFS root-fs. Even when USB is used previously in U-Boot.
Without this patch NFS booting hangs randomly at some time.

So:

Tested-by: Stefan Roese <sr at denx.de>

Note: I think its a bit too late to take this patch into this release.
So I suggest to apply it in the next merge-window.

Thanks,
Stefan