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authorÁlvaro Fernández Rojas <noltari@gmail.com>2016-12-02 11:50:26 +0100
committerÁlvaro Fernández Rojas <noltari@gmail.com>2016-12-04 12:32:04 +0100
commit011f2c26f1b62e309f2eac6a3101bfe0a3c76c7e (patch)
treebe53d4f11f7625508ee3aea9889e854ab5b5f263 /target/linux/brcm2708/patches-4.4/0404-dmaengine-bcm2835-Fix-cyclic-DMA-period-splitting.patch
parent4257f6548b9480cdb436115b63d5c134c5e91303 (diff)
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brcm2708: update linux 4.4 patches to latest version
As usual these patches were extracted and rebased from the raspberry pi repo: https://github.com/raspberrypi/linux/tree/rpi-4.4.y Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Diffstat (limited to 'target/linux/brcm2708/patches-4.4/0404-dmaengine-bcm2835-Fix-cyclic-DMA-period-splitting.patch')
-rw-r--r--target/linux/brcm2708/patches-4.4/0404-dmaengine-bcm2835-Fix-cyclic-DMA-period-splitting.patch38
1 files changed, 38 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.4/0404-dmaengine-bcm2835-Fix-cyclic-DMA-period-splitting.patch b/target/linux/brcm2708/patches-4.4/0404-dmaengine-bcm2835-Fix-cyclic-DMA-period-splitting.patch
new file mode 100644
index 0000000..a2fba2e
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.4/0404-dmaengine-bcm2835-Fix-cyclic-DMA-period-splitting.patch
@@ -0,0 +1,38 @@
+From 60026ebc9abd3e719f56db57c482679176ae8881 Mon Sep 17 00:00:00 2001
+From: Matthias Reichl <hias@horus.com>
+Date: Tue, 7 Jun 2016 19:37:10 +0200
+Subject: [PATCH] dmaengine: bcm2835: Fix cyclic DMA period splitting
+
+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>
+---
+ 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
+@@ -252,8 +252,11 @@ 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;