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@linuxfoundation.org Sent: Tuesday, February 9, 2021 6:23 PM To: Obayashi, Yoshimasa/尾林 善正 obayashi.yoshimasa@socionext.com Cc: sumit.garg@linaro.org; hch@lst.de; m.szyprowski@samsung.com; robin.murphy@arm.com; iommu@lists.linux-foundation.org; linux-kernel@vger.kernel.org; stable@vger.kernel.org; daniel.thompson@linaro.org 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@socionext.com 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