Re: [PATCH v2 1/2] usb: dwc2: host: Fix missing device insertions

[Alan Stern]

On Mon, 16 Nov 2015, Doug Anderson wrote:

> > Fundamentally there's no difference between a "connect" interrupt and a
> > "disconnect" interrupt.  They should both do exactly the same things:
> > clear the interrupt source, post a "connection change" event, and set
> > the driver's connect status based on the hardware's current state.
> > The second and third parts can be handled by a shared subroutine.
> 
> Ah, sorry I misunderstood.  OK, fair enough.  So you're saying that
> the problem is that dwc2_hcd_disconnect() has a line that looks like
> this:
> 
>   hsotg->flags.b.port_connect_status = 0;
> 
> ...and the dwc2_port_intr() has a line that looks like this:
> 
>   hsotg->flags.b.port_connect_status = 1;
> 
> ...and both should just query the status.

Well, I don't know how the driver uses flags.b.port_connect_status.  In 
principle it could do away with that flag completely and always query 
the hardware status.

> Do you think we should to block landing this patch on cleaning up how
> dwc2 handles port_connect_status?  I'm not sure what side effects
> changing port_connect_status will have, so I'll need to test and dig a
> bit...
> 
> I'm currently working on trying to fix the microframe scheduler and
> was planning to post the next series of patches there pretty soon.
> I'm also planning to keep digging to figure out how to overall
> increase compatibility with devices (and compatibility with many
> devices plugged in).
> 
> If it were up to me, I'd prefer to land this patch in either 4.4 or
> 4.5 since it does seem to work.  ...then put seeing what we can do to
> cleanup all of the port_connect_status on the todo list.

It's up to you guys.  All I've been doing here is pointing out that
your proposed approach didn't seem like the best.

Alan Stern

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/