media: atomisp: Fix "stop stream timeout." error

Commit c7194b21809e ("media: atomisp: On streamoff wait for buffers owned
by the CSS to be given back") added draining of the CSS buffer queue to
the beginning of atomisp_stop_stream().

But it turns out that when telling the CSS to stop streaming it needs at
least 1 buffer queued, because the CSS firmware waits for a frame to be
completed before stopping and without buffers it cannot complete a frame.

At the end of atomisp_stop_stream() it is always safe to return buffer
ownership to the videobuf2-core. Either atomisp_css_stop() has successfully
stopped the stream; or the atomisp_reset() later on which power-cycles
the ISP will definitely have stopped the stream.

Drop the draining of the CSS buffer queue to fix the "stop stream timeout."
error and move the atomisp_flush_video_pipe() call after atomisp_reset(),
passing false for the warn_on_css_frames flag since some buffers still
being marked as owned by the CSS expected on stream off.

Also increase the timeout in destroy_stream(), since this waits for
the last frame to be completed this can take longer then 40 ms. When e.g.
using a framerate of 15 fps, this could take 66ms, make the timeout 200 ms
to be on the safe side.

Signed-off-by: Hans de Goede <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/staging/media/atomisp/pci/atomisp_compat_css20.c

···
 	}
 
 	if (stream_env->stream_state == CSS_STREAM_STARTED) {
-		timeout = jiffies + msecs_to_jiffies(40);
+		timeout = jiffies + msecs_to_jiffies(200);
 		while (1) {
 			if (ia_css_stream_has_stopped(stream_env->stream))
 				break;

drivers/staging/media/atomisp/pci/atomisp_fops.c

···
 	if (WARN_ON(css_pipe_id >= IA_CSS_PIPE_ID_NUM))
 		return -EINVAL;
 
-	if (pipe->stopping)
-		return -EINVAL;
-
 	space = ATOMISP_CSS_Q_DEPTH - atomisp_buffers_in_css(pipe);
 	while (space--) {
 		struct ia_css_frame *frame;
···
 	mutex_lock(&asd->isp->mutex);
 
 	ret = atomisp_pipe_check(pipe, false);
-	if (ret || pipe->stopping) {
+	if (ret) {
 		spin_lock_irqsave(&pipe->irq_lock, irqflags);
 		atomisp_buffer_done(frame, VB2_BUF_STATE_ERROR);
 		spin_unlock_irqrestore(&pipe->irq_lock, irqflags);

drivers/staging/media/atomisp/pci/atomisp_ioctl.c

···
 	unsigned long flags;
 	int ret;
 
-	/*
-	 * There is no guarantee that the buffers queued to / owned by the ISP
-	 * will properly be returned to the queue when stopping. Set a flag to
-	 * avoid new buffers getting queued and then wait for all the current
-	 * buffers to finish.
-	 */
-	pipe->stopping = true;
-	mutex_unlock(&isp->mutex);
-	/* wait max 1 second */
-	ret = wait_event_timeout(pipe->vb_queue.done_wq,
-				 atomisp_buffers_in_css(pipe) == 0, HZ);
-	mutex_lock(&isp->mutex);
-	pipe->stopping = false;
-	if (ret == 0)
-		dev_warn(isp->dev, "Warning timeout waiting for CSS to return buffers\n");
-
 	spin_lock_irqsave(&isp->lock, flags);
 	asd->streaming = false;
 	spin_unlock_irqrestore(&isp->lock, flags);
···
 	atomisp_css_irq_enable(isp, IA_CSS_IRQ_INFO_CSS_RECEIVER_SOF, false);
 
 	atomisp_css_stop(asd, false);
-
-	atomisp_flush_video_pipe(pipe, state, true);
 
 	atomisp_subdev_cleanup_pending_events(asd);
 
···
 	pci_write_config_dword(pdev, PCI_I_CONTROL,
 			       isp->saved_regs.i_control | MRFLD_PCI_I_CONTROL_SRSE_RESET_MASK);
 	atomisp_reset(isp);
+
+	atomisp_flush_video_pipe(pipe, state, false);
 
 	/* Streams were destroyed by atomisp_css_stop(), recreate them. */
 	ret = atomisp_create_pipes_stream(&isp->asd);

drivers/staging/media/atomisp/pci/atomisp_subdev.h

···
 	/* Filled through atomisp_get_css_frame_info() on queue setup */
 	struct ia_css_frame_info frame_info;
 
-	/* Set from streamoff to disallow queuing further buffers in CSS */
-	bool stopping;
-
 	/*
 	 * irq_lock is used to protect video buffer state change operations and
 	 * also to make activeq and capq operations atomic.