Hi Sekhar, On 07/21/2017 05:18 PM, Alexandre Bailon wrote: > Hi Sekhar, > > On 07/10/2017 01:00 PM, Sekhar Nori wrote: > > On Thursday 06 July 2017 10:43 PM, Alexandre Bailon wrote: > >> On 06/29/2017 03:50 PM, Sekhar Nori wrote: > >>> Hi Alexandre, Bin, > >>> > >>> With latest linux-next, I see a warning dump when I remove g_zero[1] on > >>> OMAP-L138 LCDK board. I am building the kernel with davinci_all_defconfig. > >>> > >>> It is not present in latest mainline because the warnings are introduced > >>> with CPPI DMA getting enabled in latest -next. > >>> > >>> Subsequent insertion of g_ether leads to a warning too[2], although the > >>> gadget seems to work (ping test). > >>> > >>> Since these are pretty annoying, it will be nice to get rid of them. I > >>> have not been able to debug any further. But if you have > >>> ideas/experiments to try, I can do that. > > > >> I got a lot of these warnings during development but it was only for the > >> host mode. > >> If I remember correctly, the cause was a race between the teardown > >> function and the interrupt handler. > >> The teardwon descriptor was pop from the queue by the interrupt handler, > >> preventing cppi41_tear_down_chan() to get it, which will result after > >> some retries to a couple of warnings. > >> > >> I will take a look to see if that is the same issue. > That is not the same issue. Still, for some reasons, we never get the > teardown descriptor. > Two possibilities: > - Like the issue I had, the teardown is pop at the wrong place. > - The teardown doesn't complete or the descriptor is not queued. The teardown descriptor is not queued. I have figured out the reason. The function cppi41_dma_channel_abort() enable the teardown by setting the bit corresponding to the endpoint number. The address of the register is USB_TDOWN but actually the address is wrong in the case of DA8xx. Using the right address (0x1c) fix the teardown warnings. I will work on a fix. > I think we should eliminate the first one before to work on the second one. > I think adding some logs to cppi41_pop_desc() could help to figure out > what is happening. > > > > Thanks! I also see similar warnings under fast ping traffic and g_ether > > inserted on LCDK. They dont come immediately though. Only after an hour > > or so under traffic. The fix should also fix this issue. > I would not have expected to have them during a ping but this probably > happens because some USB packet have timed out, which cause may a teardown. > > > > I can those provide logs too if its going to be helpful. > Currently, I think we should focus on the warnings that happens during > the rmmod as they are always reproducible. > > Thanks, > Alexandre > Note that the teardown is not the only thing that doesn't work correctly. I think same kind of issue should apply to the autoreq and the dma mode. I will work on a patch that should solve all of them. Thanks, Alexandre -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
