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From: Alan Stern <stern@rowland.harvard.edu>
To: Ming Lei <tom.leiming@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Ming Lei <ming.lei@canonical.com>, <linux-media@vger.kernel.org>,
	<linux-usb@vger.kernel.org>,
	Jeremy Kerr <jeremy.kerr@canonical.com>,
	Mauro Carvalho Chehab <mchehab@redhat.com>
Subject: Re: [PATCH] uvcvideo: add fix suspend/resume quirk for Microdia camera
Date: Wed, 13 Jul 2011 11:59:53 -0400 (EDT)	[thread overview]
Message-ID: <Pine.LNX.4.44L0.1107131154390.2156-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <CACVXFVPJvuzKZetupzBf+GhwZKV10EHjpNUwTz98sweH3xkd4w@mail.gmail.com>

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On Wed, 13 Jul 2011, Ming Lei wrote:

> Hi,
> 
> On Wed, Jul 13, 2011 at 11:20 PM, Alan Stern <stern@rowland.harvard.edu> wrote:
> 
> > Why should system suspend be different from runtime suspend?  Have you
> 
> This is also my puzzle, :-)
> 
> > compared usbmon traces for the two types of suspend?
> 
> Almost same.

Come on.  "Almost same" means they are different.  That difference is
clearly the important thing you need to track down.

>  If I add USB_QUIRK_RESET_RESUME quirk for the device,
> the stream data will not be received from the device in runtime pm case,
> same with that in system suspend.

uvcvideo should be able to reinitialize the device so that it works
correctly following a reset.  If the device doesn't work then uvcvideo
has a bug in its reset_resume handler.

> Maybe buggy BIOS makes root hub send reset signal to the device during
> system suspend time, not sure...

That's entirely possible.

Alan Stern


  reply	other threads:[~2011-07-13 15:59 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-11  9:48 [PATCH] uvcvideo: add fix suspend/resume quirk for Microdia camera Ming Lei
2011-07-11 10:44 ` Laurent Pinchart
2011-07-12  1:21   ` Ming Lei
2011-07-12 10:52     ` Ming Lei
2011-07-12 15:44       ` Alan Stern
2011-07-13  7:43         ` Ming Lei
2011-07-13 15:20           ` Alan Stern
2011-07-13 15:30             ` Ming Lei
2011-07-13 15:59               ` Alan Stern [this message]
2011-07-14  9:16                 ` Ming Lei
2011-07-14 15:03                   ` Alan Stern
2011-07-15  2:08                     ` Ming Lei
2011-07-15 13:53                     ` Ming Lei
2011-07-15 14:27                       ` Alan Stern
2011-07-15 14:44                         ` Ming Lei
2011-07-15 15:25                           ` Alan Stern
2011-07-16  3:51                             ` [PATCH] uvcvideo: add SetInterface(0) in .reset_resume handler Ming Lei
2011-07-31 15:38                               ` Laurent Pinchart
2011-08-01  0:56                                 ` Ming Lei
2011-08-01 11:26                                   ` Laurent Pinchart
2011-08-01 17:39                                     ` Mauro Carvalho Chehab
2011-08-01 22:19                                       ` [GIT PATCH FOR v3.1] uvcvideo: Set alternate setting 0 on resume if the bus has been reset Laurent Pinchart
2011-07-13  8:35         ` [PATCH] uvcvideo: add fix suspend/resume quirk for Microdia camera Ming Lei
2011-07-13  8:38     ` Laurent Pinchart
2011-07-13  8:51       ` Ming Lei
2011-07-13  8:55         ` Oliver Neukum
2011-07-13  8:59         ` Laurent Pinchart
2011-07-13  9:07           ` Ming Lei
2011-07-11 10:51 ` Sergei Shtylyov

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