Messages in this thread Patch in this message | | | From | Bartlomiej Zolnierkiewicz <> | Subject | [PATCH resend] DMA: add cpu_relax() to busy-loop in dma_sync_wait() | Date | Wed, 05 Dec 2012 12:23:48 +0100 |
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From: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Subject: [PATCH] DMA: add cpu_relax() to busy-loop in dma_sync_wait()
Removal of the busy-loop from dma_sync_wait() is not a trivial task so just add cpu_relax() to the loop for now.
Cc: Vinod Koul <vinod.koul@intel.com> Cc: Dan Williams <djbw@fb.com> Cc: Tomasz Figa <t.figa@samsung.com> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> --- drivers/dma/dmaengine.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
Index: b/drivers/dma/dmaengine.c =================================================================== --- a/drivers/dma/dmaengine.c 2012-11-07 16:12:41.776876102 +0100 +++ b/drivers/dma/dmaengine.c 2012-11-07 16:13:04.956876097 +0100 @@ -266,7 +266,10 @@ enum dma_status dma_sync_wait(struct dma pr_err("%s: timeout!\n", __func__); return DMA_ERROR; } - } while (status == DMA_IN_PROGRESS); + if (status != DMA_IN_PROGRESS) + break; + cpu_relax(); + } while (1); return status; }
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