[PATCH 4/4] mx2_camera: implement forced termination of active buffer for mx25

[Baruch Siach]

Hi Guennadi,

On Fri, Aug 27, 2010 at 11:07:31AM +0200, Guennadi Liakhovetski wrote:
> On Tue, 27 Jul 2010, Baruch Siach wrote:
> > This allows userspace to terminate a capture without waiting for the 
> > current
> > frame to complete.
> 
> This is an improvement, not a fix, right? Without this patch the 
> termination just have to wait a couple of ms longer? so, it is ok to 
> schedule it for 2.6.37?

In my situation the image data source may stop sending data in the middle of a 
frame.  In this case userspace is stuck forever. So, this is a real fix for 
me. This is not the usual use case, I guess, so I leave it for you to decide.

baruch

> > Signed-off-by: Baruch Siach <baruch at tkos.co.il>
> > ---
> >  drivers/media/video/mx2_camera.c |   20 ++++++++++++++++----
> >  1 files changed, 16 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/media/video/mx2_camera.c b/drivers/media/video/mx2_camera.c
> > index d327d11..396542b 100644
> > --- a/drivers/media/video/mx2_camera.c
> > +++ b/drivers/media/video/mx2_camera.c
> > @@ -648,15 +648,27 @@ static void mx2_videobuf_release(struct videobuf_queue *vq,
> >  	 * Terminate only queued but inactive buffers. Active buffers are
> >  	 * released when they become inactive after videobuf_waiton().
> >  	 *
> > -	 * FIXME: implement forced termination of active buffers, so that the
> > -	 * user won't get stuck in an uninterruptible state. This requires a
> > -	 * specific handling for each of the three DMA types that this driver
> > -	 * supports.
> > +	 * FIXME: implement forced termination of active buffers for mx27 and 
> > +	 * mx27 eMMA, so that the user won't get stuck in an uninterruptible
> > +	 * state. This requires a specific handling for each of the these DMA
> > +	 * types.
> >  	 */
> >  	spin_lock_irqsave(&pcdev->lock, flags);
> >  	if (vb->state == VIDEOBUF_QUEUED) {
> >  		list_del(&vb->queue);
> >  		vb->state = VIDEOBUF_ERROR;
> > +	} else if (cpu_is_mx25() && vb->state == VIDEOBUF_ACTIVE) {
> > +		if (pcdev->fb1_active == buf) {
> > +			pcdev->csicr1 &= ~CSICR1_FB1_DMA_INTEN;
> > +			writel(0, pcdev->base_csi + CSIDMASA_FB1);
> > +			pcdev->fb1_active = NULL;
> > +		} else if (pcdev->fb2_active == buf) {
> > +			pcdev->csicr1 &= ~CSICR1_FB2_DMA_INTEN;
> > +			writel(0, pcdev->base_csi + CSIDMASA_FB2);
> > +			pcdev->fb2_active = NULL;
> > +		}
> > +		writel(pcdev->csicr1, pcdev->base_csi + CSICR1);
> > +		vb->state = VIDEOBUF_ERROR;
> >  	}
> >  	spin_unlock_irqrestore(&pcdev->lock, flags);
> >  
> > -- 
> > 1.7.1
> > 
> > --
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> > 
> 
> ---
> Guennadi Liakhovetski, Ph.D.
> Freelance Open-Source Software Developer
> http://www.open-technology.de/

-- 
                                                     ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -