Re: [PATCH 1/2] media: imx: csi: Disable CSI immediately after last EOF

From: Steve Longerbeam
Date: Thu Jan 17 2019 - 15:22:39 EST

Hi Fabio, thanks for the review.

On 1/17/19 12:20 PM, Fabio Estevam wrote:
Hi Steve,

On Thu, Jan 17, 2019 at 6:15 PM Steve Longerbeam <slongerbeam@xxxxxxxxx> wrote:
Disable the CSI immediately after receiving the last EOF before stream
off (and thus before disabling the IDMA channel).

This fixes a complete system hard lockup on the SabreAuto when streaming
from the ADV7180, by repeatedly sending a stream off immediately followed
by stream on:

while true; do v4l2-ctl -d4 --stream-mmap --stream-count=3; done

Eventually this either causes the system lockup or EOF timeouts at all
subsequent stream on, until a system reset.

The lockup occurs when disabling the IDMA channel at stream off. Disabling
the CSI before disabling the IDMA channel appears to be a reliable fix for
the hard lockup.

Reported-by: GaÃl PORTAY <gael.portay@xxxxxxxxxxxxx>
Signed-off-by: Steve Longerbeam <slongerbeam@xxxxxxxxx>
Thanks. Since this fixes a lockup, maybe it is worth adding a Fixes
tag and Cc stable?

Right, forgot. I will do that and resubmit.

drivers/staging/media/imx/imx-media-csi.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c
index e18f58f56dfb..9218372cb997 100644
--- a/drivers/staging/media/imx/imx-media-csi.c
+++ b/drivers/staging/media/imx/imx-media-csi.c
@@ -681,6 +681,8 @@ static void csi_idmac_stop(struct csi_priv *priv)
if (ret == 0)
v4l2_warn(&priv->sd, "wait last EOF timeout\n");

+ ipu_csi_disable(priv->csi);
devm_free_irq(priv->dev, priv->eof_irq, priv);
devm_free_irq(priv->dev, priv->nfb4eof_irq, priv);

@@ -793,11 +795,10 @@ static void csi_stop(struct csi_priv *priv)
/* stop the frame interval monitor */
if (priv->fim)
imx_media_fim_set_stream(priv->fim, NULL, false);
+ } else {
+ ipu_csi_disable(priv->csi);
- ipu_csi_disable(priv->csi);
Unneeded line removal.

Will fix.