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

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Date:   Thu, 17 Jan 2019 12:22:30 -0800
From:   Steve Longerbeam <slongerbeam@...il.com>
To:     Fabio Estevam <festevam@...il.com>
Cc:     linux-media <linux-media@...r.kernel.org>,
        "open list:STAGING SUBSYSTEM" <devel@...verdev.osuosl.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        open list <linux-kernel@...r.kernel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Mauro Carvalho Chehab <mchehab@...nel.org>
Subject: Re: [PATCH 1/2] media: imx: csi: Disable CSI immediately after last
 EOF

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@...il.com> 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: Gaël PORTAY <gael.portay@...labora.com>
>> Signed-off-by: Steve Longerbeam <slongerbeam@...il.com>
> 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.

Steve