On Tue, Aug 11, 2015 at 02:34:29PM +0200, Sebastian Andrzej Siewior wrote: > On 08/11/2015 12:06 PM, Russell King - ARM Linux wrote: > > I think what people need to learn is that an API in the kernel which > > returns an int _can_ fail - it returns an int so it _can_ return an > > error code. If it _can_ return an error code, there _will_ be > > implementations which _do_. > > > > If you don't check the return code, either your code doesn't care whether > > the function was successful or not, or you're playing with fire. This is > > a prime example of playing with fire. > > > > Let's leave the crappy userspace laziness with regard to error checking > > to userspace, and keep it out of the kernel. > > > > Yes, the DMA engine capabilities may not be sufficient to describe every > > detail of DMA engines, but that's absolutely no reason to skimp on error > > checking. Had there been some kind of error checking at the site, this > > problem would have been spotted before the 8250-omap driver was merged. > > Let me disable RX-DMA in 8250-omap code and push that stable. Then we > won't need a special annotation for pause support because it remains > off and is currently about one user. I browsed each driver in > drivers/dma each one which does support pause supports it and all of > them implement it unconditionally (ipu_idmac grabs a mutex first but > this is another story). > Adding error checking to 8250-omap like I have it in #1 and disabling > RX-DMA in case pause fails looks be reasonable since there is nothing > else that can be done I guess. > Once we have the missing piece in omap-dma the RX-DMA can be enabled in > 8250-omap. > Does this sound like a plan we can agree on? Yes sounds good to me.. -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
