Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Date:   Tue, 2 Jun 2020 21:10:49 +0900
To:     Hans Verkuil <hverkuil@xs4all.nl>
Cc:     Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Hans Verkuil <hans.verkuil@cisco.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Tomasz Figa <tfiga@chromium.org>, linux-media@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: Re: [PATCH v6 03/14] videobuf2: handle V4L2 buffer cache flags
Message-ID: <20200602121049.GB617@jagdpanzerIV.localdomain>
References: <20200514160153.3646-1-sergey.senozhatsky@gmail.com>
 <20200514160153.3646-4-sergey.senozhatsky@gmail.com>
 <b34ae09b-7c20-7255-6adc-3370680555cd@xs4all.nl>
 <20200602101834.GA617@jagdpanzerIV.localdomain>
 <9ec2618b-0cce-b00e-08cf-b579d9aa1d5d@xs4all.nl>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <9ec2618b-0cce-b00e-08cf-b579d9aa1d5d@xs4all.nl>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On (20/06/02 12:27), Hans Verkuil wrote:
[..]
> > Sorry, Hans, do you suggest to have something like this:
> > 
> > 	if (q->memory == VB2_MEMORY_DMABUF) {
> > 		vb->need_cache_sync_on_finish = 0;
> > 		vb->need_cache_sync_on_prepare = 0;
> > 		b->flags &= ~V4L2_BUF_FLAG_NO_CACHE_INVALIDATE;
> > 		b->flags &= ~V4L2_BUF_FLAG_NO_CACHE_CLEAN;
> > 		return;
> > 	}
> > 
> > I didn't clear the ->flags there because we clear the vb flush/sync
> > flags: ->need_cache_sync_on_finish/prepare are zeros for DMABUF memory
> > type. Which is equivalent to passing V4L2_BUF_FLAG_NO_CACHE_INVALIDATE
> > V4L2_BUF_FLAG_NO_CACHE_CLEAN. IOW we would clearing both "vb's do cache
> > sync" and request's "do not cache sync".
> 
> Ah, yes. In that case the v4l-utils patch is likely wrong.
> Can you take a look at that patch?

Hans, are we talking about "v4l2-utils: test cache_hints for MMAP queues"
patch? I can take a look, yes.

	-ss