Hi Geert,
On Monday 17 August 2015 16:03:52 Geert Uytterhoeven wrote:
> On Sat, Aug 15, 2015 at 1:42 AM, Laurent Pinchart wrote:
> > From 131968befd5de3400631b879b1574beea27b8239 Mon Sep 17 00:00:00 2001
> > From: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> > Date: Sat, 15 Aug 2015 01:28:28 +0300
> > Subject: [PATCH] dmaengine: rcar-dmac: Fix residue reporting for pending
> >
> > descriptors
> >
> > Cookies corresponding to pending transfers have a residue value equal to
> > the full size of the corresponding descriptor. The driver miscomputes
> > that and uses the size of the active descriptor instead. Fix it.
>
> Thanks!
>
> > Reported-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> > Signed-off-by: Laurent Pinchart
> > <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> > ---
> >
> > drivers/dma/sh/rcar-dmac.c | 28 ++++++++++++++++++++++++++--
> > 1 file changed, 26 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
> > index 7820d07e7bee..a98596a1f12f 100644
> > --- a/drivers/dma/sh/rcar-dmac.c
> > +++ b/drivers/dma/sh/rcar-dmac.c
> > @@ -1143,19 +1143,43 @@ static unsigned int
> > rcar_dmac_chan_get_residue(struct rcar_dmac_chan *chan,
> > struct rcar_dmac_desc *desc = chan->desc.running;
> > struct rcar_dmac_xfer_chunk *running = NULL;
> > struct rcar_dmac_xfer_chunk *chunk;
> > + enum dma_status status;
> > unsigned int residue = 0;
> > unsigned int dptr = 0;
> >
> > if (!desc)
> > return 0;
> > +
> > + /*
> > + * If the cookie corresponds to a descriptor that has been
> > completed
> > + * there is no residue. The same check has already been performed
> > by the
> > + * caller but without holding the channel lock, so the descriptor
> > could
> > + * now be complete.
> > + */
> > + status = dma_cookie_status(&chan->chan, cookie, NULL);
> > + if (status == DMA_COMPLETE)
> > + return 0;
> > +
> > /*
> > * If the cookie doesn't correspond to the currently running
> > transfer
> > * then the descriptor hasn't been processed yet, and the residue
> > is
> > * equal to the full descriptor size.
> > */
> > - if (cookie != desc->async_tx.cookie)
> > - return desc->size;
> > + if (cookie != desc->async_tx.cookie) {
> > + list_for_each_entry(desc, &chan->desc.pending, node) {
> > + if (cookie == desc->async_tx.cookie)
> > + return desc->size;
> > + }
>
> The descriptor may be either on the pending or active list, so I had to add
>
> + list_for_each_entry(desc, &chan->desc.active, node) {
> + if (cookie == desc->async_tx.cookie)
> + return desc->size;
> + }
>
> After that it seems to work fine. Will do more testing...
My bad. I'll fix that and submit the patch. Thank you for testing it.
> > +
> > + /*
> > + * No descriptor found for the cookie, there's thus no
> > residue.
> > + * This shouldn't happen if the calling driver passes a
> > correct
> > + * cookie value.
> > + */
> > + WARN(1, "No descriptor for cookie!");
> > + return 0;
> > + }
--
Regards,
Laurent Pinchart
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