* [RESEND PATCH] dmaengine: bcm2835: Fix cyclic DMA period splitting
@ 2017-02-20 19:01 ` Matthias Reichl
0 siblings, 0 replies; 4+ messages in thread
From: Matthias Reichl @ 2017-02-20 19:01 UTC (permalink / raw)
To: Vinod Koul, Stephen Warren, Lee Jones, Eric Anholt
Cc: Martin Sperl, Clive Messer, dmaengine, linux-rpi-kernel,
linux-arm-kernel, linux-kernel
The code responsible for splitting periods into chunks that
can be handled by the DMA controller missed to update total_len,
the number of bytes processed in the current period, when there
are more chunks to follow.
Therefore total_len was stuck at 0 and the code didn't work at all.
This resulted in a wrong control block layout and audio issues because
the cyclic DMA callback wasn't executing on period boundaries.
Fix this by adding the missing total_len update.
Signed-off-by: Matthias Reichl <hias@horus.com>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Tested-by: Clive Messer <clive.messer@digitaldreamtime.co.uk>
Reviewed-by: Eric Anholt <eric@anholt.net>
---
drivers/dma/bcm2835-dma.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index 80d35f7..599c218 100644
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -253,8 +253,11 @@ static void bcm2835_dma_create_cb_set_length(
*/
/* have we filled in period_length yet? */
- if (*total_len + control_block->length < period_len)
+ if (*total_len + control_block->length < period_len) {
+ /* update number of bytes in this period so far */
+ *total_len += control_block->length;
return;
+ }
/* calculate the length that remains to reach period_length */
control_block->length = period_len - *total_len;
--
2.1.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* [RESEND PATCH] dmaengine: bcm2835: Fix cyclic DMA period splitting
@ 2017-02-20 19:01 ` Matthias Reichl
0 siblings, 0 replies; 4+ messages in thread
From: Matthias Reichl @ 2017-02-20 19:01 UTC (permalink / raw)
To: linux-arm-kernel
The code responsible for splitting periods into chunks that
can be handled by the DMA controller missed to update total_len,
the number of bytes processed in the current period, when there
are more chunks to follow.
Therefore total_len was stuck at 0 and the code didn't work at all.
This resulted in a wrong control block layout and audio issues because
the cyclic DMA callback wasn't executing on period boundaries.
Fix this by adding the missing total_len update.
Signed-off-by: Matthias Reichl <hias@horus.com>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Tested-by: Clive Messer <clive.messer@digitaldreamtime.co.uk>
Reviewed-by: Eric Anholt <eric@anholt.net>
---
drivers/dma/bcm2835-dma.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index 80d35f7..599c218 100644
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -253,8 +253,11 @@ static void bcm2835_dma_create_cb_set_length(
*/
/* have we filled in period_length yet? */
- if (*total_len + control_block->length < period_len)
+ if (*total_len + control_block->length < period_len) {
+ /* update number of bytes in this period so far */
+ *total_len += control_block->length;
return;
+ }
/* calculate the length that remains to reach period_length */
control_block->length = period_len - *total_len;
--
2.1.4
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [RESEND PATCH] dmaengine: bcm2835: Fix cyclic DMA period splitting
2017-02-20 19:01 ` Matthias Reichl
@ 2017-02-22 2:41 ` Vinod Koul
-1 siblings, 0 replies; 4+ messages in thread
From: Vinod Koul @ 2017-02-22 2:41 UTC (permalink / raw)
To: Matthias Reichl, Stephen Warren, Lee Jones, Eric Anholt,
Martin Sperl, Clive Messer, dmaengine, linux-rpi-kernel,
linux-arm-kernel, linux-kernel
On Mon, Feb 20, 2017 at 08:01:16PM +0100, Matthias Reichl wrote:
> The code responsible for splitting periods into chunks that
> can be handled by the DMA controller missed to update total_len,
> the number of bytes processed in the current period, when there
> are more chunks to follow.
>
> Therefore total_len was stuck at 0 and the code didn't work at all.
> This resulted in a wrong control block layout and audio issues because
> the cyclic DMA callback wasn't executing on period boundaries.
>
> Fix this by adding the missing total_len update.
Applied, thanks
--
~Vinod
^ permalink raw reply [flat|nested] 4+ messages in thread
* [RESEND PATCH] dmaengine: bcm2835: Fix cyclic DMA period splitting
@ 2017-02-22 2:41 ` Vinod Koul
0 siblings, 0 replies; 4+ messages in thread
From: Vinod Koul @ 2017-02-22 2:41 UTC (permalink / raw)
To: linux-arm-kernel
On Mon, Feb 20, 2017 at 08:01:16PM +0100, Matthias Reichl wrote:
> The code responsible for splitting periods into chunks that
> can be handled by the DMA controller missed to update total_len,
> the number of bytes processed in the current period, when there
> are more chunks to follow.
>
> Therefore total_len was stuck at 0 and the code didn't work at all.
> This resulted in a wrong control block layout and audio issues because
> the cyclic DMA callback wasn't executing on period boundaries.
>
> Fix this by adding the missing total_len update.
Applied, thanks
--
~Vinod
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2017-02-22 2:41 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2017-02-20 19:01 [RESEND PATCH] dmaengine: bcm2835: Fix cyclic DMA period splitting Matthias Reichl
2017-02-20 19:01 ` Matthias Reichl
2017-02-22 2:41 ` Vinod Koul
2017-02-22 2:41 ` Vinod Koul
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