> How do you judge "mature"? My basic criteria are * Function is exist, but bug fix is necessary: "mature" * Function extension is necessary: "immature" > And again, if a feature isn't present in a specific kernel version, why would you think that it would be > a viable solution for you to use? So, "a feature isn't present in a specific kernel version", also means "immature" according to my criteria. Regards. > -----Original Message----- > From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> > Sent: Tuesday, February 9, 2021 6:23 PM > To: Obayashi, Yoshimasa/尾林 善正 <obayashi.yoshimasa@xxxxxxxxxxxxx> > Cc: sumit.garg@xxxxxxxxxx; hch@xxxxxx; m.szyprowski@xxxxxxxxxxx; robin.murphy@xxxxxxx; > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx; > daniel.thompson@xxxxxxxxxx > Subject: Re: DMA direct mapping fix for 5.4 and earlier stable branches > > On Tue, Feb 09, 2021 at 09:05:40AM +0000, obayashi.yoshimasa@xxxxxxxxxxxxx wrote: > > > > As the drivers are currently under development and Socionext has > > > > chosen 5.4 stable kernel for their development. So I will let > > > > Obayashi-san answer this if it's possible for them to migrate to > > > > 5.10 instead? > > > > We have started this development project from last August, so we > > have selected 5.4 as most recent and longest lifetime LTS version at > > that time. > > > > And we have already finished to develop other device drivers, and > > Video converter and CODEC drivers are now in development. > > > > > Why pick a kernel that doesn not support the features they require? > > > That seems very odd and unwise. > > > > From the view point of ZeroCopy using DMABUF, is 5.4 not mature > > enough, and is 5.10 enough mature ? > > This is the most important point for judging migration. > > How do you judge "mature"? > > And again, if a feature isn't present in a specific kernel version, why would you think that it would be > a viable solution for you to use? > > good luck! > > greg k-h
