Hello,
> > * I have a test program, http://pmeerw.net/scaler.c, which exercises the
> > OMAP3 ISP resizer standalone with the pipeline given below; it crashes the
> > system quite reliably on 3.7 and recent kernels :(
> >
> > the reason for the crash is that the ISP resizer can still be busy and
> > doesn't like to be turned off then; a little sleep before
> > omap3isp_sbl_disable() helps (or waiting for the ISP resize to become
> > idle, see the patch below)
> >
> > I'm not sure what omap3isp_module_sync_idle() is supposed to do, it
> > immediately returns since we are in SINGLESHOT mode and
> > isp_pipeline_ready() is false
>
> The function is supposed to wait until the module becomes idle. I'm not sure
> why we don't call it for memory-to-memory pipelines, I need to investigate
> that. Sakari, do you remember what we've done there ?
>
> > with below patch I am happily resizing...
> >
> > // snip, RFC
> > From: Peter Meerwald <[email protected]>
> > Date: Wed, 12 Feb 2014 15:59:20 +0100
> > Subject: [PATCH] omap3isp: Wait for resizer to become idle before
> > disabling
> >
> > ---
> > drivers/media/platform/omap3isp/ispresizer.c | 10 ++++++++++
> > 1 file changed, 10 insertions(+)
> >
> > diff --git a/drivers/media/platform/omap3isp/ispresizer.c
> > b/drivers/media/platform/omap3isp/ispresizer.c
> > index d11fb26..fea98f7 100644
> > --- a/drivers/media/platform/omap3isp/ispresizer.c
> > +++ b/drivers/media/platform/omap3isp/ispresizer.c
> > @@ -1145,6 +1145,7 @@ static int resizer_set_stream(struct v4l2_subdev *sd,
> > int enable) struct isp_video *video_out = &res->video_out;
> > struct isp_device *isp = to_isp_device(res);
> > struct device *dev = to_device(res);
> > + unsigned long timeout = 0;
> >
> > if (res->state == ISP_PIPELINE_STREAM_STOPPED) {
> > if (enable == ISP_PIPELINE_STREAM_STOPPED)
> > @@ -1176,6 +1177,15 @@ static int resizer_set_stream(struct v4l2_subdev *sd,
> > int enable) if (omap3isp_module_sync_idle(&sd->entity, &res->wait,
> > &res->stopping))
> > dev_dbg(dev, "%s: module stop timeout.\n",
> > sd->name);
> > +
> > + while (omap3isp_resizer_busy(res)) {
> > + if (timeout++ > 1000) {
> > + dev_alert(isp->dev, "ISP resizer does not
> > become idle\n");
> > + return -ETIMEDOUT;
> > + }
> > + udelay(100);
> > + }
> > +
>
> Let's try to avoid busy loops if possible. Does it help if you comment out
> the
> condition at the top of omap3isp_module_sync_idle() ?
>
> > omap3isp_sbl_disable(isp, OMAP3_ISP_SBL_RESIZER_READ |
> > OMAP3_ISP_SBL_RESIZER_WRITE);
> > omap3isp_subclk_disable(isp, OMAP3_ISP_SUBCLK_RESIZER);
tried without the check at the top of omap3isp_module_sync_idle()
I am not sure yet when and how many interrupts occur in memory-to-memory
(singleshot) mode... and the code might be racy:
if the resizer is done, we don't want to wait for another interrupt which
might never happen;
if the resizer is not done (how do we know?), we need to test that and
set the stopping flag so that omap3isp_module_sync_is_stopping() wakes us
when done
omap3isp_module_sync_idle():
if (pipe->stream_state == ISP_PIPELINE_STREAM_STOPPED ||
(0 && pipe->stream_state == ISP_PIPELINE_STREAM_SINGLESHOT &&
!isp_pipeline_ready(pipe)))
return 0;
isp_pipeline_ready() seems to be the wrong check for resizer done;
the final interrupt could occur here, before setting 'stopping'
/*
* atomic_set() doesn't include memory barrier on ARM platform for SMP
* scenario. We'll call it here to avoid race conditions.
*/
atomic_set(stopping, 1);
regards, p.
--
Peter Meerwald
+43-664-2444418 (mobile)
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