| Message ID | 1365517986-9401-1-git-send-email-peter.ujfalusi@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Apr 09, 2013 at 04:33:06PM +0200, Peter Ujfalusi wrote: > cyclic DMA is only used by audio which needs DMA to be started without a > delay. > If the DMA for audio is started using the tasklet we experience random > channel switch (to be more precise: channel shift). > > Reported-by: Peter Meerwald <pmeerw@pmeerw.net> > CC: stable@vger.kernel.org # v3.7+ > Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> > Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> > Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> > --- > Hi Vinod, > > Would it be possible to send this patch for 3.9. The channel shift (or switch) > issue in audio has been noticed recently and it turns out that it has been > present since 3.7 kernel. > It would be great if 3.9 kernel could work correctly out of box... Applied to fixes. I will send this to linus in a day... -- ~Vinod > > Changes since RFCv2: > - added Acked-by from Santosh and Russell > > Thank you, > Peter > > drivers/dma/omap-dma.c | 20 ++++++++++++++------ > 1 file changed, 14 insertions(+), 6 deletions(-) > > diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c > index 2ea3d7e..ec3fc4f 100644 > --- a/drivers/dma/omap-dma.c > +++ b/drivers/dma/omap-dma.c > @@ -282,12 +282,20 @@ static void omap_dma_issue_pending(struct dma_chan *chan) > > spin_lock_irqsave(&c->vc.lock, flags); > if (vchan_issue_pending(&c->vc) && !c->desc) { > - struct omap_dmadev *d = to_omap_dma_dev(chan->device); > - spin_lock(&d->lock); > - if (list_empty(&c->node)) > - list_add_tail(&c->node, &d->pending); > - spin_unlock(&d->lock); > - tasklet_schedule(&d->task); > + /* > + * c->cyclic is used only by audio and in this case the DMA need > + * to be started without delay. > + */ > + if (!c->cyclic) { > + struct omap_dmadev *d = to_omap_dma_dev(chan->device); > + spin_lock(&d->lock); > + if (list_empty(&c->node)) > + list_add_tail(&c->node, &d->pending); > + spin_unlock(&d->lock); > + tasklet_schedule(&d->task); > + } else { > + omap_dma_start_desc(c); > + } > } > spin_unlock_irqrestore(&c->vc.lock, flags); > } > -- > 1.8.1.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c index 2ea3d7e..ec3fc4f 100644 --- a/drivers/dma/omap-dma.c +++ b/drivers/dma/omap-dma.c @@ -282,12 +282,20 @@ static void omap_dma_issue_pending(struct dma_chan *chan) spin_lock_irqsave(&c->vc.lock, flags); if (vchan_issue_pending(&c->vc) && !c->desc) { - struct omap_dmadev *d = to_omap_dma_dev(chan->device); - spin_lock(&d->lock); - if (list_empty(&c->node)) - list_add_tail(&c->node, &d->pending); - spin_unlock(&d->lock); - tasklet_schedule(&d->task); + /* + * c->cyclic is used only by audio and in this case the DMA need + * to be started without delay. + */ + if (!c->cyclic) { + struct omap_dmadev *d = to_omap_dma_dev(chan->device); + spin_lock(&d->lock); + if (list_empty(&c->node)) + list_add_tail(&c->node, &d->pending); + spin_unlock(&d->lock); + tasklet_schedule(&d->task); + } else { + omap_dma_start_desc(c); + } } spin_unlock_irqrestore(&c->vc.lock, flags); }