From: Lu Baolu <baolu.lu@linux.intel.com>
To: Jun Li <jun.li@nxp.com>, Roger Quadros <rogerq@ti.com>,
Peter Chen <hzpeterchen@gmail.com>
Cc: "felipe.balbi@linux.intel.com" <felipe.balbi@linux.intel.com>,
Mathias Nyman <mathias.nyman@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Lee Jones <lee.jones@linaro.org>,
Heikki Krogerus <heikki.krogerus@linux.intel.com>,
Liam Girdwood <lgirdwood@gmail.com>,
Mark Brown <broonie@kernel.org>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v10 2/7] usb: mux: add generic code for dual role port mux
Date: Tue, 7 Jun 2016 17:53:31 +0800 [thread overview]
Message-ID: <5756999B.9020809@linux.intel.com> (raw)
In-Reply-To: <AM4PR04MB2130809FDDC36F2C7F8C0F25895D0@AM4PR04MB2130.eurprd04.prod.outlook.com>
Hi,
On 06/07/2016 11:03 AM, Jun Li wrote:
> Hi Roger
>
>>
>> For Mux devices implementing dual-role, the mux device driver _must_ use
>> OTG/dual-role core API so that a common ABI is presented to user space for
>> OTG/dual-role.
> That's the only point we have concern, do dual role switch through
> OTG/dual-role core, not do it by itself.
>
>> I haven't yet looked at the mux framework but if we take care of the above
>> point then we are not introducing any redundancy.
>>
> Roger, actually this is my worry on OTG core: those dual role switch
> users just tends to do it simply by itself(straightforward and easy),
> not through the OTG core(some complicated in first look),
I'm sorry, but I'm really confused.
Why do we need to drop "straightforward and easy", but have to run
an *unnecessary* OTG state machine? Don't you think that will (1) add
*unnecessary* software complexity; (2) increase *unnecessary* memory
footprint; and (3) increase the debugging efforts?
> this is just an example for us to convince people to select a better
> way:)
Sure. Let's take my case for an example.
My system has a third-party port mux, which is not part any USB controllers.
Also, my system doesn't have any DRD capable devices. I need a
"straightforward and easy" driver for it. Otherwise, the system could not be
waken up from system suspend.
But you said I must run an unnecessary OTG state machine, even thought it
has nothing to do with my system, only because the two sides of my port
mux device is a host and peripheral controller.
Why?
Best regards,
Lu Baolu
next prev parent reply other threads:[~2016-06-07 9:53 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-02 1:37 [PATCH v10 0/7] usb: add support for Intel dual role port mux Lu Baolu
2016-06-02 1:37 ` [PATCH v10 1/7] regulator: fixed: add support for ACPI interface Lu Baolu
2016-06-08 4:42 ` Greg Kroah-Hartman
2016-06-08 13:43 ` Mark Brown
2016-06-08 15:46 ` Greg Kroah-Hartman
2016-06-09 2:43 ` Lu Baolu
2016-06-02 1:37 ` [PATCH v10 2/7] usb: mux: add generic code for dual role port mux Lu Baolu
2016-06-03 7:41 ` Peter Chen
2016-06-03 8:16 ` Heikki Krogerus
2016-06-03 9:20 ` Peter Chen
2016-06-03 16:06 ` Lu Baolu
2016-06-04 2:28 ` Peter Chen
2016-06-05 6:55 ` Lu Baolu
2016-06-05 8:33 ` Jun Li
2016-06-05 8:46 ` Lu Baolu
2016-06-06 1:08 ` Jun Li
2016-06-06 2:30 ` Lu Baolu
2016-06-06 2:05 ` Peter Chen
2016-06-06 2:45 ` Lu Baolu
2016-06-06 6:48 ` Peter Chen
2016-06-06 1:25 ` Peter Chen
2016-06-06 3:04 ` Lu Baolu
2016-06-06 7:02 ` Roger Quadros
2016-06-07 3:03 ` Jun Li
2016-06-07 6:27 ` Lu Baolu
2016-06-07 6:34 ` Jun Li
2016-06-07 9:27 ` Lu Baolu
2016-06-07 12:49 ` Roger Quadros
2016-06-07 9:53 ` Lu Baolu [this message]
2016-06-07 12:58 ` Roger Quadros
2016-06-07 13:04 ` Felipe Balbi
2016-06-07 14:02 ` Roger Quadros
2016-06-07 15:05 ` Felipe Balbi
2016-06-08 3:04 ` Jun Li
[not found] ` <5757A8CB.90402@linux.intel.com>
2016-06-08 6:20 ` Jun Li
2016-06-08 6:25 ` Peter Chen
2016-06-08 7:58 ` Roger Quadros
2016-06-06 7:02 ` Peter Chen
2016-06-06 7:35 ` Lu Baolu
2016-06-02 1:37 ` [PATCH v10 3/7] usb: mux: add driver for Intel gpio controlled " Lu Baolu
2016-06-02 1:37 ` [PATCH v10 4/7] usb: mux: add driver for Intel drcfg " Lu Baolu
2016-06-02 1:37 ` [PATCH v10 5/7] mfd: intel_vuport: Add Intel virtual USB port MFD Driver Lu Baolu
2016-06-02 1:37 ` [PATCH v10 6/7] usb: pci-quirks: add Intel USB drcfg mux device Lu Baolu
2016-06-08 4:45 ` Greg Kroah-Hartman
2016-06-08 7:56 ` Lu Baolu
2016-06-08 15:45 ` Greg Kroah-Hartman
2016-06-09 2:39 ` Lu Baolu
2016-06-16 0:27 ` Lu Baolu
2016-06-18 0:58 ` Greg Kroah-Hartman
2016-06-19 9:52 ` Lu Baolu
2016-06-02 1:37 ` [PATCH v10 7/7] MAINTAINERS: add maintainer entry for Intel USB dual role mux drivers Lu Baolu
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