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From: Felipe Balbi <balbi@ti.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Zhuang Jin Can <jin.can.zhuang@intel.com>,
	Felipe Balbi <balbi@ti.com>, <linux-usb@vger.kernel.org>,
	<linux-omap@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] usb: dwc3: gadget: fix burst size corruption
Date: Thu, 1 May 2014 10:15:00 -0500	[thread overview]
Message-ID: <20140501151500.GC6355@saruman.home> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1405010941550.1152-100000@iolanthe.rowland.org>

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Hi,

On Thu, May 01, 2014 at 09:45:17AM -0400, Alan Stern wrote:
> On Thu, 1 May 2014, Zhuang Jin Can wrote:
> 
> > > again, you found a bug on the gadget driver. Fix that. composite.c
> > > guarantees that for those functions which don't pass bMaxBurst,
> > > gadget->maxburst will be set to *at least* 1.
> > > 
> > I agree the real fix should be in the gadget driver. The patch intents
> > to prevent hibernatition from being corrupted by a bad gadget driver.
> > If OEMs develop their own gadget driver forgetting to call
> > config_ep_by_speed(), it'll turn out to be everything works except
> > dwc3 hibernation, and they'll complain to dwc3. f_ffs is an
> > example has SuperSpeed support but doesn't call config_ep_by_speed().
> > It's just for robustness, and dwc3 is not doing anything wrong.
> > It did cause me a long time to figure out why the hibernation was broken.
> 
> You could include the check, for the sake of robustness, in dwc3 -- but
> if it fails, you should write a message to the kernel log saying that
> the gadget driver needs to be fixed.

Also, if we're adding something to dwc3, we need to add to other
USB3-capable UDCs too. Namely dummy and marvel's.

cheers

-- 
balbi

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WARNING: multiple messages have this Message-ID (diff)
From: Felipe Balbi <balbi@ti.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Zhuang Jin Can <jin.can.zhuang@intel.com>,
	Felipe Balbi <balbi@ti.com>,
	linux-usb@vger.kernel.org, linux-omap@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] usb: dwc3: gadget: fix burst size corruption
Date: Thu, 1 May 2014 10:15:00 -0500	[thread overview]
Message-ID: <20140501151500.GC6355@saruman.home> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1405010941550.1152-100000@iolanthe.rowland.org>

[-- Attachment #1: Type: text/plain, Size: 1233 bytes --]

Hi,

On Thu, May 01, 2014 at 09:45:17AM -0400, Alan Stern wrote:
> On Thu, 1 May 2014, Zhuang Jin Can wrote:
> 
> > > again, you found a bug on the gadget driver. Fix that. composite.c
> > > guarantees that for those functions which don't pass bMaxBurst,
> > > gadget->maxburst will be set to *at least* 1.
> > > 
> > I agree the real fix should be in the gadget driver. The patch intents
> > to prevent hibernatition from being corrupted by a bad gadget driver.
> > If OEMs develop their own gadget driver forgetting to call
> > config_ep_by_speed(), it'll turn out to be everything works except
> > dwc3 hibernation, and they'll complain to dwc3. f_ffs is an
> > example has SuperSpeed support but doesn't call config_ep_by_speed().
> > It's just for robustness, and dwc3 is not doing anything wrong.
> > It did cause me a long time to figure out why the hibernation was broken.
> 
> You could include the check, for the sake of robustness, in dwc3 -- but
> if it fails, you should write a message to the kernel log saying that
> the gadget driver needs to be fixed.

Also, if we're adding something to dwc3, we need to add to other
USB3-capable UDCs too. Namely dummy and marvel's.

cheers

-- 
balbi

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  reply	other threads:[~2014-05-01 15:15 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-01  7:16 [PATCH] usb: dwc3: gadget: fix burst size corruption Zhuang Jin Can
2014-04-30 20:03 ` Felipe Balbi
2014-04-30 20:03   ` Felipe Balbi
2014-05-01 21:14   ` Zhuang Jin Can
2014-05-01 13:45     ` Alan Stern
2014-05-01 13:45       ` Alan Stern
2014-05-01 15:15       ` Felipe Balbi [this message]
2014-05-01 15:15         ` Felipe Balbi
2014-05-03  3:35         ` Zhuang Jin Can

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