Re: [PATCH v4 0/3] media: imx: Stop stream before disabling IDMA channels

[Steve Longerbeam <slongerbeam@gmail.com>]

Hi Hans,

On 1/21/19 11:34 PM, Hans Verkuil wrote:
> Hi Steve,
>
> On 01/22/2019 12:35 AM, Steve Longerbeam wrote:
>> Repeatedly sending a stream off immediately followed by stream on can
>> eventually cause a complete system hard lockup on the SabreAuto when
>> streaming from the ADV7180:
>>
>> 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 channels at stream off. Stopping
>> the video data stream entering the IDMA channel before disabling the
>> channel itself appears to be a reliable fix for the hard lockup.
>>
>> In the CSI subdevice, this can be done by disabling the CSI before
>> disabling the CSI IDMA channel, instead of after. In the IC-PRPENVVF
>> subdevice, this can be done by stopping upstream before disabling the
>> PRPENC/VF IDMA channel.
> Please let me know when you are satisfied with this patch series and I
> can make a pull request for this.

I'm satisfied with it now, it addresses Philipp's concerns from v3.

Also Gael reported successful testing.

Steve


>
> Thanks!
>
> 	Hans
>
>> History:
>> v4:
>> - Disabling SMFC will have no effect if both CSI's are streaming. So
>>    go back to disabling CSI before channel as in v2, but split up
>>    csi_idmac_stop such that ipu_csi_disable can still be called within
>>    csi_stop.
>>
>> v3:
>> - Switch to disabling the SMFC before the channel, instead of the CSI
>>    before the channel.
>>
>> v2:
>> - Whitespace fixes
>> - Add Fixes: and Cc: stable@vger.kernel.org
>> - No functional changes.
>>
>>
>> Steve Longerbeam (3):
>>    media: imx: csi: Disable CSI immediately after last EOF
>>    media: imx: csi: Stop upstream before disabling IDMA channel
>>    media: imx: prpencvf: Stop upstream before disabling IDMA channel
>>
>>   drivers/staging/media/imx/imx-ic-prpencvf.c | 26 ++++++++-----
>>   drivers/staging/media/imx/imx-media-csi.c   | 42 +++++++++++++--------
>>   2 files changed, 44 insertions(+), 24 deletions(-)
>>