[U-Boot] [PATCH 2/2] usb: fix usb start problem with SMSC USB hub and Toshiba USB stick

[Wolfgang Denk]

Dear Remy Bohmer,

In message <AANLkTikqEFtB=XEAV1G6xyvOY3HW3imCPiFiLD0kVoG6 at mail.gmail.com> you wrote:
> 
> > +       if (dev->descriptor.idVendor == 0x930 &&
> > +           dev->descriptor.idProduct == 0x6545 &&
> > +           dev->parent->descriptor.idVendor == 0x424 &&
> > +           dev->parent->descriptor.idProduct == 0x2514)
> > +               wait_ms(10);
> > +
>
> I have to say that I have a problem with this construction.
> This will solve only 1 particular situation where the user has exactly
> this USB stick and exactly this hub.
> If he uses another hub, he can have the same problem. If he use
> another USB-stick he also can run into this problem.
> What is the real cause of this issue, and can it be solved in a
> generic way? I feel the problem is still not understood.

Indeed the problem is not exactly understood.

Anatolij has tested a wide range of board / hub / stick combinations,
and the problem happens only with this very combination.

Yes, there is a chance that another hub / stick combination might show
similar issues, but so far we have not been able to find such another
combo.

> So, I NAK this patch.. Sorry...

So what do you propose to solve the problem?  Of course we could add
the delay unconditionally, for all systems.  But it brings with it a
performance degradation which I would not like to see either.

What do you suggest to provide a solution for this specific situation?

Best regards,

Wolfgang Denk

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