After audio full duplex testing, playing the recorded file contains a few
playback frames for the first time. The rz_dmac_terminate_all() does not
reset all the hardware descriptors queued previously, leading to the wrong
descriptor being picked up during the next DMA transfer. Fix this issue by
resetting all descriptor headers for a channel in rz_dmac_terminate_all()
as rz_dmac_lmdesc_recycle() points to the proper descriptor header filled
by the rz_dmac_prepare_descs_for_slave_sg().

Cc: stable@kernel.org
Fixes: 5000d37042a6 ("dmaengine: sh: Add DMAC driver for RZ/G2L SoC")
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
---
 drivers/dma/sh/rz-dmac.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
index 1f687b08d6b8..3087bbd11d59 100644
--- a/drivers/dma/sh/rz-dmac.c
+++ b/drivers/dma/sh/rz-dmac.c
@@ -557,11 +557,16 @@ rz_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 static int rz_dmac_terminate_all(struct dma_chan *chan)
 {
 	struct rz_dmac_chan *channel = to_rz_dmac_chan(chan);
+	struct rz_lmdesc *lmdesc = channel->lmdesc.base;
 	unsigned long flags;
+	unsigned int i;
 	LIST_HEAD(head);
 
 	rz_dmac_disable_hw(channel);
 	spin_lock_irqsave(&channel->vc.lock, flags);
+	for (i = 0; i < DMAC_NR_LMDESC; i++)
+		lmdesc[i].header = 0;
+
 	list_splice_tail_init(&channel->ld_active, &channel->ld_free);
 	list_splice_tail_init(&channel->ld_queue, &channel->ld_free);
 	vchan_get_all_descriptors(&channel->vc, &head);
-- 
2.43.0

On 11/6/25 14:52, Biju Das wrote:
> After audio full duplex testing, playing the recorded file contains a few
> playback frames for the first time. The rz_dmac_terminate_all() does not
> reset all the hardware descriptors queued previously, leading to the wrong
> descriptor being picked up during the next DMA transfer. Fix this issue by
> resetting all descriptor headers for a channel in rz_dmac_terminate_all()
> as rz_dmac_lmdesc_recycle() points to the proper descriptor header filled
> by the rz_dmac_prepare_descs_for_slave_sg().
> 
> Cc: stable@kernel.org
> Fixes: 5000d37042a6 ("dmaengine: sh: Add DMAC driver for RZ/G2L SoC")
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>

Reviewed-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Tested-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>

> ---
>  drivers/dma/sh/rz-dmac.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
> index 1f687b08d6b8..3087bbd11d59 100644
> --- a/drivers/dma/sh/rz-dmac.c
> +++ b/drivers/dma/sh/rz-dmac.c
> @@ -557,11 +557,16 @@ rz_dmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
>  static int rz_dmac_terminate_all(struct dma_chan *chan)
>  {
>  	struct rz_dmac_chan *channel = to_rz_dmac_chan(chan);
> +	struct rz_lmdesc *lmdesc = channel->lmdesc.base;
>  	unsigned long flags;
> +	unsigned int i;
>  	LIST_HEAD(head);
>  
>  	rz_dmac_disable_hw(channel);
>  	spin_lock_irqsave(&channel->vc.lock, flags);
> +	for (i = 0; i < DMAC_NR_LMDESC; i++)
> +		lmdesc[i].header = 0;
> +
>  	list_splice_tail_init(&channel->ld_active, &channel->ld_free);
>  	list_splice_tail_init(&channel->ld_queue, &channel->ld_free);
>  	vchan_get_all_descriptors(&channel->vc, &head);

Hi Biju,

Thanks for your patch!

On Thu, 6 Nov 2025 at 13:53, Biju Das <biju.das.jz@bp.renesas.com> wrote:
> After audio full duplex testing, playing the recorded file contains a few
> playback frames for the first time. The rz_dmac_terminate_all() does not

... frames from the previous time?

> reset all the hardware descriptors queued previously, leading to the wrong
> descriptor being picked up during the next DMA transfer. Fix this issue by
> resetting all descriptor headers for a channel in rz_dmac_terminate_all()
> as rz_dmac_lmdesc_recycle() points to the proper descriptor header filled
> by the rz_dmac_prepare_descs_for_slave_sg().
>
> Cc: stable@kernel.org
> Fixes: 5000d37042a6 ("dmaengine: sh: Add DMAC driver for RZ/G2L SoC")
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>

The code change LGTM, so
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds