On Tue, Sep 8, 2020 at 11:58 PM Tomasz Figa <tfiga@xxxxxxxxxxxx> wrote: > > Hi Hans, Mauro, > > On Tue, Sep 1, 2020 at 5:02 PM Tomasz Figa <tfiga@xxxxxxxxxxxx> wrote: > > > > On Tue, Sep 1, 2020 at 1:06 PM Christoph Hellwig <hch@xxxxxx> wrote: > > > > > > On Thu, Aug 20, 2020 at 07:33:48PM +0200, Tomasz Figa wrote: > > > > > It wasn't meant to be too insulting, but I found this out when trying > > > > > to figure out how to just disable it. But it also ends up using > > > > > the actual dma attr flags for it's own consistency checks, so just > > > > > not setting the flag did not turn out to work that easily. > > > > > > > > > > > > > Yes, sadly the videobuf2 ended up becoming quite counterintuitive > > > > after growing for the long years and that is reflected in the design > > > > of this feature as well. I think we need to do something about it. > > > > > > So I'm about to respin the series and wonder how we should proceed. > > > I've failed to come up with a clean patch to keep the flag and make > > > it a no-op. Can you or your team give it a spin? > > > > > > > Okay, I'll take a look. > > > > > Also I wonder if the flag should be renamed from NON_CONSISTENT > > > to NON_COHERENT - the consistent thing is a weird wart from the times > > > the old PCI DMA API that is mostly gone now. > > > > It originated from the DMA_ATTR_NON_CONSISTENT flag, but agreed that > > NON_COHERENT would be more consistent (pun not intended) with the rest > > of the DMA API given the removal of that flag. Let me see if we can > > still change it. > > Given the above, we would like to make changes that affect the UAPI. > Would you still be able to revert this series? Sorry, I just realized that this isn't the original series that introduced the thing, but rather a patch that does a partial revert. I think it could be also applied as an alternative for the revert, but perhaps a full series revert is just safer at this point? For reference, the series in question is: https://patchwork.linuxtv.org/project/linux-media/cover/20200514160153.3646-1-sergey.senozhatsky@xxxxxxxxx/ Best regards, tomasz
