Re: [Spca50x-devs] [BUG] kernel stall in spca50x driver

[thomas schorpp <t.schorpp@xxxxxx>]

thomas schorpp wrote:
> thomas schorpp wrote:
> 
>>hello,
>>
>>touching ekiga gui video sliders triggers spurious stalls of 2.6 kernels.
>>
>>any clue? it occours more often on touching the contrast slider.
>>color and hue seems not to be affected.
>>usb seems not affected - no stall until touching sliders.
>>
>>this will be hard to debug since there will be no kernel oops and 
>>no logs on serial cable console too.
>>the kernel seems to lock up in a endless loop somewhere.
>>
>>2.6.15.0 K7 kernel.org
>>aiptek dv3500 webcam mode
>>ekiga cvs + libs cvs
>>
>>y
>>tom
>>
> 
> 
> any grabber triggers.
> 
> the stall seems to occur if light gets too dark (black picture).
> 
no also occurs on picture change.

> here are debug logs until deadlock (serial console gets no oops, even only once so far flashing keyboard lights):
> 
> 

> Jan 20 18:47:01 tom2 kernel: /usr/src/spca5xx-20060101/drivers/usb/spca5xx.c: [spca5xx_do_ioctl:4920] syncing to frame 0, grabstate = 2

ive tried this, cause i expected deadlock on FRAME_ERROR but didnt do any better, 
deadlock should occur in the grabber thread firing the event instead(?):

	PDEBUG (4, "syncing to frame %d, grabstate = %d", frame,
		spca50x->frame[frame].grabstate);

	switch (spca50x->frame[frame].grabstate)
	  {
	  case FRAME_UNUSED:
	    return -EINVAL;
	  case FRAME_ABORTING:
	    return -ENODEV;
	  case FRAME_READY:
	  case FRAME_GRABBING:
	  //redo:			XXXX
	    if (!spca50x->dev)
	      return -EIO;

		ret = wait_event_interruptible_timeout (spca50x->frame[frame].wq,
					    (spca50x->frame[frame].
					     grabstate == FRAME_DONE),
						HZ*250);
	    if (ret)
	      return -EINTR;

	    PDEBUG (4, "Synch Ready on frame %d, grabstate = %d",
		    frame, spca50x->frame[frame].grabstate);

/*	    if (spca50x->frame[frame].grabstate == FRAME_ERROR)  XXXX
	      {
		goto redo;
	      }*/
	    /* Fallthrough.
	     * We have waited in state FRAME_GRABBING until it
	     * becomes FRAME_DONE, so now we can move along.
	     */
	  case FRAME_DONE:
	  case FRAME_ERROR: XXX

	   

	    /* Release the current frame. This means that it
	     * will be reused as soon as all other frames are
	     * full, so the app better be done with it quickly.
	     * Can this be avoided somehow?
	     */
	    spca50x->frame[frame].grabstate = FRAME_UNUSED;
		 PDEBUG (4, "Release frame %d state %d\n", frame,spca50x->frame[frame].grabstate);
	    break;
	  }			/* end switch */

	return 0;
      }





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