linux-kernel - Re: [PATCHv2] usb: gadget: get rid of USB_GADGET_DUALSPEED and USB_GADGET

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Date:	Fri, 19 Aug 2011 14:17:40 +0200
From:	"Michal Nazarewicz" <mina86@...a86.com>
To:	"Yang Rui Rui" <ruirui.r.yang@...to.com>
Cc:	"Alan Stern" <stern@...land.harvard.edu>,
	"Sergei Shtylyov" <sshtylyov@...sta.com>,
	"Felipe Balbi" <balbi@...com>,
	"Sebastian Andrzej Siewior" <bigeasy@...utronix.de>,
	"Yang Ruirui R" <ruirui.r.yang@...toenator.com>,
	"Greg Kroah-Hartman" <gregkh@...e.de>,
	"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCHv2] usb: gadget: get rid of USB_GADGET_DUALSPEED and
 USB_GADGET_SUPERSPEED

> On 08/19/2011 01:05 AM, Michal Nazarewicz wrote:
>> For the most part, usb_composite_probe() is called only once in module's
>> init function.  As far as I know, only g_ffs calls it several times.  So
>> in all cases expect for g_ffs, composite_driver.speed =
>> min(composite_driver.speed,
>> driver->max_speed) should have the same effect as composite_driver.speed
>> = driver->max_speed.

On Fri, 19 Aug 2011 04:02:00 +0200, Yang Rui Rui <ruirui.r.yang@...to.com>  
wrote:
> For original code, ifndef CONFIG_USB_GADGET_SUPERSPEED and max_speed =  
> USB_SPEED_SUPER then the result will be:
>
> composite_driver.speed = min(USB_SPEED_HIGH, USB_SPEED_SUPER)
>
> For patched code, composite_driver.speed = USB_SPEED_SUPER

OK, I see your point.  This is the issue that we are discussing in another
“branch” of the thread.  It seems either usb_gadget_driver_probe() should
make sure driver->speed is not too high or each UDC need to handle gadgets
which support speed higher then the UDC can handle.

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michal "mina86" Nazarewicz    (o o)
ooo +-----<email/xmpp: mnazarewicz@...gle.com>-----ooO--(_)--Ooo--
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