On Wed, Oct 16, 2013 at 02:06:30PM +0530, Shevchenko, Andriy wrote: > On Wed, 2013-10-16 at 11:08 +0530, Vinod Koul wrote: > > On Tue, Oct 15, 2013 at 08:55:20AM -0700, Dan Williams wrote: > > > On Tue, Oct 15, 2013 at 11:31 AM, Youquan Song > > > <youquan.s...@linux.intel.com> wrote: > > > > On Sun, Oct 13, 2013 at 08:56:33PM +0530, Vinod Koul wrote: > > > >> On Fri, Oct 11, 2013 at 06:33:43AM -0700, Greg KH wrote: > > > >> > On Fri, Oct 11, 2013 at 05:42:17PM -0400, Youquan Song wrote: > > > > The issue is that when I using UART to transfer data between to COMs > > > > which using Designware DMA controller channel. But I check the specific > > > > DMA channel by "cat /sys/class/dma/dma0chan3/bytes_transferred", but it > > > > should all "0". I have transferred data by UART port, why its DMA > > > > channel report "0" bytes transferred? So I guess that it is possible > > > > the DMA device driver issue or the data does not use the Designware DMA > > > > channel > > > > fro transferred. After check the code, I notice only when the DMA > > > > channel used by network device driver and it will record how much data > > > > has been > > > > tranferred, why other device driver will not calculate it. Since DMA > > > > channel is used by other device driver, why only network is specific? > > > > since it is > > > > common interface, the current > > > > /sys/class/dma/dma0chan*/bytes_transferred has > > > > much possibility to mislead the user. > > > > > > Yes, and for that reason I think we should delete " > > > /sys/class/dma/dma0chan*/bytes_transferred" it really serves no useful > > > purpose besides "is my dma channel working" which can be determined by > > > other means. > > Well am going to take it a bit further and ask you why do we need the > > /sys/class/dma? I have never used it for slave work. > > How user (who, f.e., would like to run dmatest) will know names of the > channels provided? Ok dmatest requires this, I overlooked that part
> How could we see what channels of certain dma controller are requested / > busy from userspace? But do end user care or need to know about this? -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
