From: Roman Mamedov <rm@romanrm.net>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org
Subject: Re: Not enough bandwidth for new device state -- with Etron USB3 controller only
Date: Thu, 22 Apr 2021 16:08:13 +0500 [thread overview]
Message-ID: <20210422160813.41e26426@natsu> (raw)
In-Reply-To: <YIEOcvePnzGlQtoy@kroah.com>
Hello,
On Thu, 22 Apr 2021 07:49:38 +0200
Greg KH <gregkh@linuxfoundation.org> wrote:
> Not a bug, this is how USB works. Your first hub really does not have
> enough bandwidth for that device. Well, we think it doesn't, the
> calculation for that is really really tricky and we error on the side of
> "let's not take the risk and just disable the device to be safe".
>
> Get a better hub :)
But why the calculation is different when the hub is plugged into the onboard
USB 2.0 controller -- and there it works?
I hope you don't take this as a bug report to make it stop working there as
well. :)
If it's because the Etron controller is USB 3.0, and the higher speeds are
somehow accounted for in the bandwidth calculation, that doesn't seem right,
since both of the plugged in downstream hubs are 1.1/2.0-only.
--
With respect,
Roman
next prev parent reply other threads:[~2021-04-22 11:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-21 17:37 Not enough bandwidth for new device state -- with Etron USB3 controller only Roman Mamedov
2021-04-22 5:49 ` Greg KH
2021-04-22 11:08 ` Roman Mamedov [this message]
2021-04-22 11:15 ` Greg KH
2021-04-22 14:21 ` Alan Stern
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