From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 05/28] media/v4l2: remove V4L2-FLAG-MEMORY-NON-CONSISTENT Date: Thu, 20 Aug 2020 18:54:07 +0200 Message-ID: <20200820165407.GD12693@lst.de> References: <20200819065555.1802761-1-hch@lst.de> <20200819065555.1802761-6-hch@lst.de> <20200819135454.GA17098@lst.de> <20200820044347.GA4533@lst.de> <20200820052004.GA5305@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Sender: "iommu" To: Tomasz Figa Cc: alsa-devel-K7yf7f+aM1XWsZ/bQMPhNw@public.gmane.org, linux-ia64-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Linux Doc Mailing List , nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, linux-nvme-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Linux Kernel Mailing List , "James E.J. Bottomley" , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, Christoph Hellwig , linux-samsung-soc , Joonyoung Shim , linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "list-Y9sIeH5OGRo@public.gmane.org:IOMMU DRIVERS , Joerg Roedel , " , Ben Skeggs , Matt Porter , Linux Media Mailing List , Tom Lendacky , Pawel Osciak , Mauro Carvalho Chehab list-Y9sIeH5OGRo@public.gmane.org:IOMMU DRIVERS List-Id: nouveau.vger.kernel.org On Thu, Aug 20, 2020 at 12:05:29PM +0200, Tomasz Figa wrote: > The UAPI and V4L2/videobuf2 changes are in good shape and the only > wrong part is the use of DMA API, which was based on an earlier email > guidance anyway, and a change to the synchronization part . I find > conclusions like the above insulting for people who put many hours > into designing and implementing the related functionality, given the > complexity of the videobuf2 framework and how ill-defined the DMA API > was, and would feel better if such could be avoided in future > communication. 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. But in general it helps to add a few more people to the Cc list for such things that do stranger things. Especially if you think you did it based on the advice of those people.