[U-Boot] USB power is not enabled fro BeagleBone Black

[Aaron Williams]

One thing we have come across is that some USB drives require a longer delay 
between powering up and initialization.

I have historically also run into a lot of problems with both Sandisk USB 
devices and Sandisk SD cards, finding instances where they do not follow the 
standards.

-Aaron

On Thursday, July 27, 2017 1:42:02 PM PDT Sergey Manucharian wrote:
> New findings:
> 
> The problem is different, it happens only with USB 3 flash drives, USB 2
> devices are powered properly. I don't have real statistics, but the
> newest SanDisk's drives won't work.
> 
> However, it's hard to believe that a tiny USB drive requests more than
> 500mA to assume that the controller and/or u-boot decide to not provide
> power to it.
> 
> Sergey
> 
> Excerpts from Lokesh Vutla's message from Mon 10-Jul-17 18:47:
> > On 7/8/2017 8:50 AM, Sergey Manucharian wrote:
> > > (sorry for top posting, sending from a phone)
> > > 
> > > I would agree it's intentional at the first stage: we don't want to
> > > power external devices which we may not need, however, the "usb start"
> > > command must enable it, otherwise it's useless...> 
> > Right. Any chance you bisected to the commit which caused the issue?
> > 
> > Thanks and regards,
> > Lokesh
> > 
> > > -S.
> > > 
> > >   Original Message
> > > 
> > > From: Tom Rini
> > > Sent: Friday, July 7, 2017 18:41
> > > To: sm; Lokesh Vutla
> > > Cc: u-boot at lists.denx.de
> > > Subject: Re: [U-Boot] USB power is not enabled fro BeagleBone Black
> > > 
> > > On Sat, Jul 01, 2017 at 12:51:41PM -0700, sm wrote:
> > >> Hi all,
> > >> 
> > >> The latest git version does not turn on USB power on BeagleBone Black:
> > >> "usb start" reports that the port is not accessible, but with external
> > >> power provided it detects the plugged in device.
> > > 
> > > Yes, I think this may be intentional?
> 
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-- 
Aaron Williams
Senior Software Engineer
Cavium, Inc.
(408) 943-7198	(510) 789-8988 (cell)