On 08/07/2015 06:07 PM, Peter Hurley wrote:

quoted

If we look at what 8250-dma.c is doing:

                if (dma->rx_running) {
                        dmaengine_pause(dma->rxchan);

It's 8250-dma.c which is silently _ignoring_ the return code, failing
to check that the operation it requested worked.  Maybe this should be
WARN_ON(dmaengine_pause(dma->rxchan)) or at least it should print a
message?

Thanks for the suggestion; I'll hold on to that and push it after we add
the 8250 omap dma pause in mainline.

I have a patch ready with WARN_ON_ONCE() for 8250-omap and 8250-dma.
This warning would trigger on am335x/edma until v4.2-rc1 and omap-dma
based version is open. I could post it if you want me to.
Besides that those two, there are four other drivers ignoring the
return code dmaengine_pause().

Sebastian