Disable the SMFC before disabling the IDMA channel, instead of after, in csi_idmac_unsetup().
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. Stopping the video data stream entering the IDMA channel before disabling the channel itself appears to be a reliable fix for the hard lockup. That can be done either by disabling the SMFC or the CSI before disabling the channel. Disabling the SMFC before the channel is the easiest solution, so do that.
Fixes: 4a34ec8e470cb ("[media] media: imx: Add CSI subdev driver")
Suggested-by: Peter Seiderer ps.report@gmx.net Reported-by: Gaël PORTAY gael.portay@collabora.com Signed-off-by: Steve Longerbeam slongerbeam@gmail.com Cc: stable@vger.kernel.org --- Changes in v3: - switch from disabling the CSI before the channel to disabling the SMFC before the channel. Changes in v2: - restore an empty line - Add Fixes: and Cc: stable --- drivers/staging/media/imx/imx-media-csi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c index e18f58f56dfb..8610027eac97 100644 --- a/drivers/staging/media/imx/imx-media-csi.c +++ b/drivers/staging/media/imx/imx-media-csi.c @@ -560,8 +560,8 @@ static int csi_idmac_setup_channel(struct csi_priv *priv) static void csi_idmac_unsetup(struct csi_priv *priv, enum vb2_buffer_state state) { - ipu_idmac_disable_channel(priv->idmac_ch); ipu_smfc_disable(priv->smfc); + ipu_idmac_disable_channel(priv->idmac_ch);
csi_idmac_unsetup_vb2_buf(priv, state); }
Hi,
On Fri, 2019-01-18 at 17:04 -0800, Steve Longerbeam wrote:
Disable the SMFC before disabling the IDMA channel, instead of after, in csi_idmac_unsetup().
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. Stopping the video data stream entering the IDMA channel before disabling the channel itself appears to be a reliable fix for the hard lockup. That can be done either by disabling the SMFC or the CSI before disabling the channel. Disabling the SMFC before the channel is the easiest solution, so do that.
Fixes: 4a34ec8e470cb ("[media] media: imx: Add CSI subdev driver")
Suggested-by: Peter Seiderer ps.report@gmx.net Reported-by: Gaël PORTAY gael.portay@collabora.com Signed-off-by: Steve Longerbeam slongerbeam@gmail.com
Gaël, could we get a Tested-by: for this as well?
Cc: stable@vger.kernel.org
Changes in v3:
- switch from disabling the CSI before the channel to disabling the SMFC before the channel.
Changes in v2:
- restore an empty line
- Add Fixes: and Cc: stable
drivers/staging/media/imx/imx-media-csi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c index e18f58f56dfb..8610027eac97 100644 --- a/drivers/staging/media/imx/imx-media-csi.c +++ b/drivers/staging/media/imx/imx-media-csi.c @@ -560,8 +560,8 @@ static int csi_idmac_setup_channel(struct csi_priv *priv) static void csi_idmac_unsetup(struct csi_priv *priv, enum vb2_buffer_state state) {
- ipu_idmac_disable_channel(priv->idmac_ch); ipu_smfc_disable(priv->smfc);
- ipu_idmac_disable_channel(priv->idmac_ch);
Steve, do you have any theory why this helps? It's a bit weird to disable the SMFC module while the DMA channel is still enabled. I think this warrants a big comment, given that enable order is SMFC_EN before IDMAC channel enable.
Also ipu_smfc_disable is refcounted, so if the other CSI is capturing simultaneously, this change has no effect.
FWIW, I don't see any regressions though.
regards Philipp
Philipp,
On Mon, Jan 21, 2019 at 12:49:10PM +0100, Philipp Zabel wrote:
Hi,
On Fri, 2019-01-18 at 17:04 -0800, Steve Longerbeam wrote:
Disable the SMFC before disabling the IDMA channel, instead of after, in csi_idmac_unsetup().
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. Stopping the video data stream entering the IDMA channel before disabling the channel itself appears to be a reliable fix for the hard lockup. That can be done either by disabling the SMFC or the CSI before disabling the channel. Disabling the SMFC before the channel is the easiest solution, so do that.
Fixes: 4a34ec8e470cb ("[media] media: imx: Add CSI subdev driver")
Suggested-by: Peter Seiderer ps.report@gmx.net Reported-by: Gaël PORTAY gael.portay@collabora.com Signed-off-by: Steve Longerbeam slongerbeam@gmail.com
Gaël, could we get a Tested-by: for this as well?
I have not tested the v3 yet. I have planned to do it later this day for a all night testing and report the result then.
Gael
On 1/21/19 3:49 AM, Philipp Zabel wrote:
Hi,
On Fri, 2019-01-18 at 17:04 -0800, Steve Longerbeam wrote:
Disable the SMFC before disabling the IDMA channel, instead of after, in csi_idmac_unsetup().
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. Stopping the video data stream entering the IDMA channel before disabling the channel itself appears to be a reliable fix for the hard lockup. That can be done either by disabling the SMFC or the CSI before disabling the channel. Disabling the SMFC before the channel is the easiest solution, so do that.
Fixes: 4a34ec8e470cb ("[media] media: imx: Add CSI subdev driver")
Suggested-by: Peter Seiderer ps.report@gmx.net Reported-by: Gaël PORTAY gael.portay@collabora.com Signed-off-by: Steve Longerbeam slongerbeam@gmail.com
Gaël, could we get a Tested-by: for this as well?
Cc: stable@vger.kernel.org
Changes in v3:
- switch from disabling the CSI before the channel to disabling the SMFC before the channel.
Changes in v2:
- restore an empty line
- Add Fixes: and Cc: stable
drivers/staging/media/imx/imx-media-csi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c index e18f58f56dfb..8610027eac97 100644 --- a/drivers/staging/media/imx/imx-media-csi.c +++ b/drivers/staging/media/imx/imx-media-csi.c @@ -560,8 +560,8 @@ static int csi_idmac_setup_channel(struct csi_priv *priv) static void csi_idmac_unsetup(struct csi_priv *priv, enum vb2_buffer_state state) {
- ipu_idmac_disable_channel(priv->idmac_ch); ipu_smfc_disable(priv->smfc);
- ipu_idmac_disable_channel(priv->idmac_ch);
Steve, do you have any theory why this helps? It's a bit weird to disable the SMFC module while the DMA channel is still enabled.
It does fix the hang, but I only have a vague theory as to why. That by disabling the DMA channel while its internal FIFO is getting filled is causing the hang, maybe due to a simultaneous update of the channel's internal FIFO write pointer and the channel disable bit. By disabling the SMFC (or the CSI), writes to the channel's internal FIFO stop.
I think this warrants a big comment, given that enable order is SMFC_EN before IDMAC channel enable.
Also ipu_smfc_disable is refcounted, so if the other CSI is capturing simultaneously, this change has no effect.
Sigh, you're right. Let me go back to disabling the CSI before the channel, the CSI enable/disable is not refcounted (it doesn't need to be since it is single use) so it doesn't have this problem.
Should we drop this patch or keep it (with a big comment)? By only changing the disable order to "CSI then channel", the hang is reliably fixed from my and Gael's testing, but my concern is that by not disabling the SMFC before the channel, the SMFC could still empty its FIFO to the channel's internal FIFO and still create a hang.
Steve
On 1/21/19 10:43 AM, Steve Longerbeam wrote:
On 1/21/19 3:49 AM, Philipp Zabel wrote:
Also ipu_smfc_disable is refcounted, so if the other CSI is capturing simultaneously, this change has no effect.
Sigh, you're right. Let me go back to disabling the CSI before the channel, the CSI enable/disable is not refcounted (it doesn't need to be since it is single use) so it doesn't have this problem.
Should we drop this patch or keep it (with a big comment)? By only changing the disable order to "CSI then channel", the hang is reliably fixed from my and Gael's testing, but my concern is that by not disabling the SMFC before the channel, the SMFC could still empty its FIFO to the channel's internal FIFO and still create a hang.
Well, as you said it will have no effect if both CSI's are streaming with the SMFC, in which case the danger would still exist. Perhaps it would be best to just drop this patch.
Steve
On Mon, 2019-01-21 at 10:46 -0800, Steve Longerbeam wrote:
On 1/21/19 10:43 AM, Steve Longerbeam wrote:
On 1/21/19 3:49 AM, Philipp Zabel wrote:
Also ipu_smfc_disable is refcounted, so if the other CSI is capturing simultaneously, this change has no effect.
Sigh, you're right. Let me go back to disabling the CSI before the channel, the CSI enable/disable is not refcounted (it doesn't need to be since it is single use) so it doesn't have this problem.
Should we drop this patch or keep it (with a big comment)? By only changing the disable order to "CSI then channel", the hang is reliably fixed from my and Gael's testing, but my concern is that by not disabling the SMFC before the channel, the SMFC could still empty its FIFO to the channel's internal FIFO and still create a hang.
Well, as you said it will have no effect if both CSI's are streaming with the SMFC, in which case the danger would still exist. Perhaps it would be best to just drop this patch.
Hm, if we can't guarantee the intended effect with this patch, and stopping the CSI first helps reliably, it's indeed better to just do that instead.
regards Philipp
Philipp,
On Mon, Jan 21, 2019 at 12:49:10PM +0100, Philipp Zabel wrote:
Hi,
On Fri, 2019-01-18 at 17:04 -0800, Steve Longerbeam wrote:
Disable the SMFC before disabling the IDMA channel, instead of after, in csi_idmac_unsetup().
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. Stopping the video data stream entering the IDMA channel before disabling the channel itself appears to be a reliable fix for the hard lockup. That can be done either by disabling the SMFC or the CSI before disabling the channel. Disabling the SMFC before the channel is the easiest solution, so do that.
Fixes: 4a34ec8e470cb ("[media] media: imx: Add CSI subdev driver")
Suggested-by: Peter Seiderer ps.report@gmx.net Reported-by: Gaël PORTAY gael.portay@collabora.com Signed-off-by: Steve Longerbeam slongerbeam@gmail.com
Gaël, could we get a Tested-by: for this as well?
I have tested the patchset v4 (not that one), and it has passed my test.
Regards, Gael
linux-stable-mirror@lists.linaro.org
-
Gaël PORTAY -
Philipp Zabel -
Steve Longerbeam