From: John Ogness Subject: [PATCH 2/3] dmaenegine: edma: allow pause/resume for non-cyclic mode Date: Mon, 27 Apr 2015 13:52:25 +0200 Message-ID: <87vbghaiva.fsf@linutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: linux-serial@vger.kernel.org, Sekhar Nori , Peter Ujfalusi , Greg Kroah-Hartman , Sebastian Andrzej Siewior List-Id: linux-serial@vger.kernel.org The 8250_omap serial driver relies on dmaengine_pause() actually pausing the DMA transfer. Before this patch dmaengine_pause() is a NOP for non-cylic DMA transfers. This allowed the 8250_omap driver to read DMA buffers while the DMA was still active, resulting in lost serial data. Signed-off-by: John Ogness --- drivers/dma/edma.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c index bf09db7..88853af 100644 --- a/drivers/dma/edma.c +++ b/drivers/dma/edma.c @@ -300,8 +300,7 @@ static int edma_dma_pause(struct dma_chan *chan) { struct edma_chan *echan = to_edma_chan(chan); - /* Pause/Resume only allowed with cyclic mode */ - if (!echan->edesc || !echan->edesc->cyclic) + if (!echan->edesc) return -EINVAL; edma_pause(echan->ch_num); @@ -312,10 +311,6 @@ static int edma_dma_resume(struct dma_chan *chan) { struct edma_chan *echan = to_edma_chan(chan); - /* Pause/Resume only allowed with cyclic mode */ - if (!echan->edesc->cyclic) - return -EINVAL; - edma_resume(echan->ch_num); return 0; } -- 1.7.10.4