Re: [PATCH 2/2] HID: hid-logitech-dj, querying_devices was neverset

From: Jiri Kosina
Date: Mon Aug 05 2013 - 09:22:23 EST


On Fri, 2 Aug 2013, Benjamin Tissoires wrote:

> > Could you please elaborate? (and put an elaborate description to revert
> > commit log perhaps?)
>
> Sure, so here is the revert commit log:
>
> --
>
> Commit "HID: hid-logitech-dj, querying_devices was never set" activate
> a flag which guarantees that we do not ask the receiver for too many
> enumeration. When the flag is set, each following enumeration call is
> discarded (the usb request is not forwarded to the receiver). The flag
> is then released when the driver receive a pairing information event,
> which normally follows the enumeration request.
> However, the USB3 bug makes the driver think the enumeration request
> has been forwarded to the receiver. However, it is actually not the
> case because the USB stack returns -EPIPE. So, when a new unknown
> device appears, the workaround consisting in asking for a new
> enumeration is not working anymore: this new enumeration is discarded
> because of the flag, which is never reset.
>
> A solution could be to trigger a timeout before releasing it, but for
> now, let's just revert the patch.
>
> --

Thanks Benjamin.

I'd like to have a bit more clarification about the USB3 bug, as this
whole issue is not completely clear to me.

To be more specific -- when exactly do we receive -EPIPE, why do we
receive it and why do we not handle it properly?

Thanks again,

--
Jiri Kosina
SUSE Labs
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