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From: Jamie Iles <jamie@jamieiles.com>
To: linux-kernel@vger.kernel.org
Cc: Jamie Iles <jamie@jamieiles.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Jamie Iles <jamie.iles@picochip.com>
Subject: [PATCH repost 1/4] dmaengine/dw_dmac: don't scan descriptors if no xfers in progress
Date: Fri, 21 Jan 2011 14:11:52 +0000	[thread overview]
Message-ID: <1295619115-18420-2-git-send-email-jamie@jamieiles.com> (raw)
In-Reply-To: <1295619115-18420-1-git-send-email-jamie@jamieiles.com>

Some hardware (picoChip picoXCell in particular) sometimes has
the block transfer complete bit being set for a channel after the
whole transfer has completed. If we don't have any transfers in the
active list then don't bother to scan the descriptors. This often
happens in normal operation and doesn't require the channel to be
reset.

v2: cleanup whitespace

Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jamie Iles <jamie.iles@picochip.com>
---
 drivers/dma/dw_dmac.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index a3991ab..db22754 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -291,6 +291,9 @@ static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
 		return;
 	}
 
+	if (list_empty(&dwc->active_list))
+		return;
+
 	dev_vdbg(chan2dev(&dwc->chan), "scan_descriptors: llp=0x%x\n", llp);
 
 	list_for_each_entry_safe(desc, _desc, &dwc->active_list, desc_node) {
-- 
1.7.3.4


  reply	other threads:[~2011-01-21 14:12 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-21 14:11 [PATCH repost 0/4] dmaengine/dw_dmac: enhancements to allow use Jamie Iles
2011-01-21 14:11 ` Jamie Iles [this message]
2011-01-21 14:11 ` [PATCH repost 2/4] dmaengine/dw_dmac: allow src/dst masters to be configured at runtime Jamie Iles
2011-01-24 14:54   ` Hans-Christian Egtvedt
2011-01-21 14:11 ` [PATCH repost 3/4] dmaengine/dw_dmac: provide a mechanism to indicate private devices Jamie Iles
2011-01-21 14:11 ` [PATCH repost 4/4] avr32: at32ap700x: specify DMA src and dst masters Jamie Iles
2011-01-24 14:59   ` Hans-Christian Egtvedt
2011-01-30  6:33     ` Dan Williams
2011-02-04 11:06       ` Jamie Iles
2011-02-21 13:45   ` Hans-Christian Egtvedt
2011-02-21 14:45     ` Jamie Iles
2011-03-15 14:56       ` Jamie Iles
2011-03-16  2:08         ` Koul, Vinod

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