| Message ID | 1375104595-16018-9-git-send-email-joelf@ti.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c index c72e8c9..0d3ebde 100644 --- a/drivers/dma/edma.c +++ b/drivers/dma/edma.c @@ -164,6 +164,12 @@ static void edma_execute(struct edma_chan *echan) edesc->total_processed += total_process; + /* If this is either the last set in a set of SG-list transactions + then setup a link to the dummy slot, this results in all future + events being absorbed and that's OK because we're done */ + if (edesc->total_processed == edesc->pset_nr) + edma_link(echan->slot[total_process-1], echan->ecc->dummy_slot); + edma_resume(echan->ch_num); if (edesc->total_processed <= MAX_NR_SG) {
Consider the case where we have a scatter-list like: SG1->SG2->SG3->SG4->SG5->SG6->Null For ex, for a MAX_NR_SG of 2, earlier we were splitting this as: SG1->SG2->Null SG3->SG4->Null SG5->SG6->Null Now we split it as SG1->SG2->Null SG3->SG4->Null SG5->SG6->Dummy This approach results in lesser unwanted interrupts that occur for the last list split. The Dummy slot has the property of not raising an error condition if events are missed unlike the Null slot. We are OK with this as we're done with processing the whole list once we reach Dummy. Signed-off-by: Joel Fernandes <joelf@ti.com> --- drivers/dma/edma.c | 6 ++++++ 1 file changed, 6 insertions(+)