Re: [PATCH 4/5] usb: gadget/uvc: Port UVC webcam gadget to use videobuf2 framework

[Felipe Balbi <balbi@ti.com>]

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Hi,

On Mon, Jun 04, 2012 at 11:37:59PM +0800, Bhupesh SHARMA wrote:
> > -----Original Message-----
> > From: Felipe Balbi [mailto:balbi@ti.com]
> > Sent: Monday, June 04, 2012 8:59 PM
> > To: Bhupesh SHARMA
> > Cc: balbi@ti.com; laurent.pinchart@ideasonboard.com; linux-
> > usb@vger.kernel.org; linux-media@vger.kernel.org;
> > gregkh@linuxfoundation.org
> > Subject: Re: [PATCH 4/5] usb: gadget/uvc: Port UVC webcam gadget to use
> > videobuf2 framework
> > 
> > On Mon, Jun 04, 2012 at 11:21:13PM +0800, Bhupesh SHARMA wrote:
> > > Hi Felipe,
> > >
> > > > -----Original Message-----
> > > > From: Felipe Balbi [mailto:balbi@ti.com]
> > > > Sent: Monday, June 04, 2012 8:44 PM
> > > > To: Bhupesh SHARMA
> > > > Cc: laurent.pinchart@ideasonboard.com; linux-usb@vger.kernel.org;
> > > > balbi@ti.com; linux-media@vger.kernel.org;
> > > > gregkh@linuxfoundation.org
> > > > Subject: Re: [PATCH 4/5] usb: gadget/uvc: Port UVC webcam gadget to
> > > > use
> > > > videobuf2 framework
> > > >
> > > > On Fri, Jun 01, 2012 at 03:08:57PM +0530, Bhupesh Sharma wrote:
> > > > > This patch reworks the videobuffer management logic present in
> > the
> > > > UVC
> > > > > webcam gadget and ports it to use the "more apt" videobuf2
> > > > > framework for video buffer management.
> > > > >
> > > > > To support routing video data captured from a real V4L2 video
> > > > > capture device with a "zero copy" operation on videobuffers (as
> > > > > they pass
> > > > from
> > > > > the V4L2 domain to UVC domain via a user-space application), we
> > > > > need to support USER_PTR IO method at the UVC gadget side.
> > > > >
> > > > > So the V4L2 capture device driver can still continue to use MMAO
> > > > > IO method and now the user-space application can just pass a
> > > > > pointer to the video buffers being DeQueued from the V4L2 device
> > > > > side while Queueing them at the UVC gadget end. This ensures that
> > > > > we have a "zero-copy" design as the videobuffers pass from the
> > > > > V4L2 capture
> > > > device to the UVC gadget.
> > > > >
> > > > > Note that there will still be a need to apply UVC specific
> > payload
> > > > > headers on top of each UVC payload data, which will still require
> > > > > a copy operation to be performed in the 'encode' routines of the
> > > > > UVC
> > > > gadget.
> > > > >
> > > > > Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com>
> > > >
> > > > this patch doesn't apply. Please refresh on top of v3.5-rc1 or my
> > > > gadget branch which I will update in a while.
> > > >
> > >
> > > I rebased and submitted my changes on your "gadget-for-v3.5" tag.
> > > Should I now refresh my patches on top of your "v3.5-rc1" branch ?
> > >
> > > I am a bit confused on what is the latest gadget branch to be used
> > now.
> > > Thanks for helping out.
> > 
> > The gadget branch is the branch called gadget on my kernel.org tree.
> > For some reason this didn't apply. Probably some patches on
> > drivers/usb/gadget/*uvc* went into v3.5 without my knowledge. Possibly
> > because I was out for quite a while and asked Greg to help me out
> > during the merge window.
> > 
> > Anyway, I just pushed gadget with a bunch of new patches and part of
> > your series.
> > 
> 
> Yes. I had sent two patches some time ago for drivers/usb/gadget/*uvc*.
> For one of them I received an *applied* message from you:

that was already applied long ago. ;-)

> 
> > > usb: gadget/uvc: Remove non-required locking from 'uvc_queue_next_buffer' routine
> 
> > > This patch removes the non-required spinlock acquire/release calls on
> > > 'queue->irqlock' from 'uvc_queue_next_buffer' routine.
> > >
> > > This routine is called from 'video->encode' function (which
> > translates
> > > to either 'uvc_video_encode_bulk' or 'uvc_video_encode_isoc') in
> > 'uvc_video.c'.
> > > As, the 'video->encode' routines are called with 'queue->irqlock'
> > > already held, so acquiring a 'queue->irqlock' again in
> > > 'uvc_queue_next_buffer' routine causes a spin lock recursion.
> > >
> > > Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com>
> > > Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > 
> > applied, thanks
> 
> Not sure, if that can cause the merge conflict issue.
> So now, should I send a clean patchset on top of your 3.5-rc1 branch to ensure
> the entire new patchset for drivers/usb/gadget/*uvc* is pulled properly?

Yes please, just give kernel.org about 20 minutes to sync all git
servers.

Just so you know, head on my gadget branch is:

commit fbcaba0e3dcec8451cccdc1fa92fcddbde2bc3f2
Author: Bhupesh Sharma <bhupesh.sharma@st.com>
Date:   Fri Jun 1 15:08:56 2012 +0530

    usb: gadget: uvc: Add super-speed support to UVC webcam gadget
    
    This patch adds super-speed support to UVC webcam gadget.
    
    Also in this patch:
        - We add the configurability to pass bInterval, bMaxBurst, mult
          factors for video streaming endpoint (ISOC IN) through module
          parameters.
    
        - We use config_ep_by_speed helper routine to configure video
          streaming endpoint.
    
    Signed-off-by: Bhupesh Sharma <bhupesh.sharma@st.com>
    Signed-off-by: Felipe Balbi <balbi@ti.com>

-- 
balbi

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