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;