From: Alan Stern <stern@rowland.harvard.edu>
To: Roger Quadros <rogerq@ti.com>
Cc: Zeng Tao <prime.zeng@hisilicon.com>, <gregkh@linuxfoundation.org>,
<mathias.nyman@linux.intel.com>, <drinkcat@chromium.org>,
<felipe.balbi@linux.intel.com>, <drake@endlessm.com>,
<mike.looijmans@topic.nl>, <joe@perches.com>,
<linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] usb: hub: try old enumeration scheme first for high speed devices
Date: Fri, 10 Aug 2018 10:19:30 -0400 (EDT) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1808101017050.1425-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <a29afa26-22b4-3188-f9ee-993e44df7703@ti.com>
On Fri, 10 Aug 2018, Roger Quadros wrote:
> Hi,
>
> On 10/08/18 18:01, Zeng Tao wrote:
> > The new scheme is required just to support legacy low and full-speed
> > devices. For high speed devices, it will slower the enumeration speed.
> > So in this patch we try the "old" enumeration scheme first for high speed
> > devices.
>
> How slow does it get? Is it significant?
> Do we risk breaking existing HS devices that work? I don't think we can
> be sure till we run this through testing.
Indeed. I am extremely skeptical about a patch like this, unless
somebody can show that Windows uses the "old" scheme for high-speed
devices.
Alan Stern
next prev parent reply other threads:[~2018-08-10 14:19 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-10 15:01 [PATCH] usb: hub: try old enumeration scheme first for high speed devices Zeng Tao
2018-08-10 10:50 ` Roger Quadros
2018-08-10 14:19 ` Alan Stern [this message]
2018-08-14 7:35 ` Zengtao (B)
2018-08-14 14:39 ` Alan Stern
2018-08-16 6:21 ` Zengtao (B)
2018-08-16 7:16 ` Roger Quadros
2018-08-16 10:59 ` Zengtao (B)
2018-08-16 11:13 ` Roger Quadros
2018-08-17 2:15 ` Zengtao (B)
2018-08-14 7:33 ` Zengtao (B)
2018-08-16 7:31 ` Roger Quadros
2018-09-28 11:27 Zeng Tao
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