From: Bartlomiej Zolnierkiewicz <[email protected]> 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 <[email protected]> Cc: Dan Williams <[email protected]> Cc: Tomasz Figa <[email protected]> Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]> Signed-off-by: Kyungmin Park <[email protected]> --- 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; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
