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Subject: Re: [Qemu-devel] [PATCH] hw/dma: Print error message only once
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To: Philipp Hahn <hahn@univention.de>, qemu-devel@nongnu.org

Il 09/09/2014 09:01, Philipp Hahn ha scritto:
> otherwise the message
> 	dma: unregistered DMA channel used nchan=0 dma_pos=0 dma_len=1
> gets printed every time and fills up the log-file with 50 MiB / minute.
> 
> Signed-off-by: Philipp Hahn <hahn@univention.de>
> ---
>  hw/dma/i8257.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/dma/i8257.c b/hw/dma/i8257.c
> index dd370ed..9673ab6 100644
> --- a/hw/dma/i8257.c
> +++ b/hw/dma/i8257.c
> @@ -473,8 +473,14 @@ static void dma_reset(void *opaque)
>  
>  static int dma_phony_handler (void *opaque, int nchan, int dma_pos, int dma_len)
>  {
> -    dolog ("unregistered DMA channel used nchan=%d dma_pos=%d dma_len=%d\n",
> -           nchan, dma_pos, dma_len);
> +    static int once;
> +    int mask = 1 << nchan;
> +
> +    if (0 == (once & mask)) {
> +        once |= mask;
> +        dolog("unregistered DMA channel used nchan=%d dma_pos=%d dma_len=%d\n",
> +              nchan, dma_pos, dma_len);
> +    }
>      return dma_pos;
>  }
>  
> 

Can you just convert it to a tracepoint and remove the message?

Thanks,

Paolo