This is a note to let you know that I've just added the patch titled
dmaengine: bcm2835: Fix cyclic DMA period splitting
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dmaengine-bcm2835-fix-cyclic-dma-period-splitting.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2201ac6129fa162ac24da089a034bb0971648ebb Mon Sep 17 00:00:00 2001
From: Matthias Reichl <hias@xxxxxxxxx>
Date: Mon, 20 Feb 2017 20:01:16 +0100
Subject: dmaengine: bcm2835: Fix cyclic DMA period splitting
From: Matthias Reichl <hias@xxxxxxxxx>
commit 2201ac6129fa162ac24da089a034bb0971648ebb upstream.
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@xxxxxxxxx>
Signed-off-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
Tested-by: Clive Messer <clive.messer@xxxxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Eric Anholt <eric@xxxxxxxxxx>
Signed-off-by: Vinod Koul <vinod.koul@xxxxxxxxx>
Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/dma/bcm2835-dma.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -251,8 +251,11 @@ static void bcm2835_dma_create_cb_set_le
*/
/* 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;
Patches currently in stable-queue which might be from hias@xxxxxxxxx are
queue-4.9/dmaengine-bcm2835-fix-cyclic-dma-period-splitting.patch