* [PATCH] dmaengine: ti: omap-dma: Skip pointless cpu_pm context restore on errors
@ 2021-05-18 7:43 Tony Lindgren
2021-05-18 11:36 ` Péter Ujfalusi
2021-05-31 4:32 ` Vinod Koul
0 siblings, 2 replies; 3+ messages in thread
From: Tony Lindgren @ 2021-05-18 7:43 UTC (permalink / raw)
To: Vinod Koul
Cc: dmaengine, linux-arm-kernel, linux-omap, Aaro Koskinen,
Adam Ford, Andreas Kemnade, Peter Ujfalusi
There's no need to restore DMA context on CPU_CLUSTER_PM_ENTER_FAILED as
the DMA context won't be lost on errors.
Note that this does not cause invalid context restore as we already check
for busy DMA with omap_dma_busy() in CPU_CLUSTER_PM_ENTER, and block any
deeper idle states for the SoC by returning NOTIFY_BAD if busy.
If other drivers block deeper idle states with cpu_pm, we now just do a
pointless restore, but only if dma was not busy on CPU_CLUSTER_PM_ENTER.
Let's update the CPU_CLUSTER_PM_ENTER_FAILED handling for correctness,
and add a comment.
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: Adam Ford <aford173@gmail.com>
Cc: Andreas Kemnade <andreas@kemnade.info>
Cc: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
drivers/dma/ti/omap-dma.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c
--- a/drivers/dma/ti/omap-dma.c
+++ b/drivers/dma/ti/omap-dma.c
@@ -1608,7 +1608,8 @@ static int omap_dma_context_notifier(struct notifier_block *nb,
return NOTIFY_BAD;
omap_dma_context_save(od);
break;
- case CPU_CLUSTER_PM_ENTER_FAILED:
+ case CPU_CLUSTER_PM_ENTER_FAILED: /* No need to restore context */
+ break;
case CPU_CLUSTER_PM_EXIT:
omap_dma_context_restore(od);
break;
--
2.31.1
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] dmaengine: ti: omap-dma: Skip pointless cpu_pm context restore on errors
2021-05-18 7:43 [PATCH] dmaengine: ti: omap-dma: Skip pointless cpu_pm context restore on errors Tony Lindgren
@ 2021-05-18 11:36 ` Péter Ujfalusi
2021-05-31 4:32 ` Vinod Koul
1 sibling, 0 replies; 3+ messages in thread
From: Péter Ujfalusi @ 2021-05-18 11:36 UTC (permalink / raw)
To: Tony Lindgren, Vinod Koul
Cc: dmaengine, linux-arm-kernel, linux-omap, Aaro Koskinen,
Adam Ford, Andreas Kemnade
On 18/05/2021 10:43, Tony Lindgren wrote:
> There's no need to restore DMA context on CPU_CLUSTER_PM_ENTER_FAILED as
> the DMA context won't be lost on errors.
>
> Note that this does not cause invalid context restore as we already check
> for busy DMA with omap_dma_busy() in CPU_CLUSTER_PM_ENTER, and block any
> deeper idle states for the SoC by returning NOTIFY_BAD if busy.
>
> If other drivers block deeper idle states with cpu_pm, we now just do a
> pointless restore, but only if dma was not busy on CPU_CLUSTER_PM_ENTER.
>
> Let's update the CPU_CLUSTER_PM_ENTER_FAILED handling for correctness,
> and add a comment.
Make sense,
Acked-by: Peter Ujfalusi <peter.ujfalusi@gmail.com>
> Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
> Cc: Adam Ford <aford173@gmail.com>
> Cc: Andreas Kemnade <andreas@kemnade.info>
> Cc: Peter Ujfalusi <peter.ujfalusi@gmail.com>
> Signed-off-by: Tony Lindgren <tony@atomide.com>
> ---
> drivers/dma/ti/omap-dma.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/ti/omap-dma.c b/drivers/dma/ti/omap-dma.c
> --- a/drivers/dma/ti/omap-dma.c
> +++ b/drivers/dma/ti/omap-dma.c
> @@ -1608,7 +1608,8 @@ static int omap_dma_context_notifier(struct notifier_block *nb,
> return NOTIFY_BAD;
> omap_dma_context_save(od);
> break;
> - case CPU_CLUSTER_PM_ENTER_FAILED:
> + case CPU_CLUSTER_PM_ENTER_FAILED: /* No need to restore context */
> + break;
> case CPU_CLUSTER_PM_EXIT:
> omap_dma_context_restore(od);
> break;
>
--
Péter
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] dmaengine: ti: omap-dma: Skip pointless cpu_pm context restore on errors
2021-05-18 7:43 [PATCH] dmaengine: ti: omap-dma: Skip pointless cpu_pm context restore on errors Tony Lindgren
2021-05-18 11:36 ` Péter Ujfalusi
@ 2021-05-31 4:32 ` Vinod Koul
1 sibling, 0 replies; 3+ messages in thread
From: Vinod Koul @ 2021-05-31 4:32 UTC (permalink / raw)
To: Tony Lindgren
Cc: dmaengine, linux-arm-kernel, linux-omap, Aaro Koskinen,
Adam Ford, Andreas Kemnade, Peter Ujfalusi
On 18-05-21, 10:43, Tony Lindgren wrote:
> There's no need to restore DMA context on CPU_CLUSTER_PM_ENTER_FAILED as
> the DMA context won't be lost on errors.
>
> Note that this does not cause invalid context restore as we already check
> for busy DMA with omap_dma_busy() in CPU_CLUSTER_PM_ENTER, and block any
> deeper idle states for the SoC by returning NOTIFY_BAD if busy.
>
> If other drivers block deeper idle states with cpu_pm, we now just do a
> pointless restore, but only if dma was not busy on CPU_CLUSTER_PM_ENTER.
>
> Let's update the CPU_CLUSTER_PM_ENTER_FAILED handling for correctness,
> and add a comment.
Applied, thanks
--
~Vinod
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-05-18 7:43 [PATCH] dmaengine: ti: omap-dma: Skip pointless cpu_pm context restore on errors Tony Lindgren
2021-05-18 11:36 ` Péter Ujfalusi
2021-05-31 4:32 ` Vinod Koul
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