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;
Date:   Sat, 28 Nov 2020 14:04:42 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To:     Tomasz Figa <tfiga@chromium.org>
Cc:     Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Hans Verkuil <hverkuil@xs4all.nl>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: Re: [PATCH] media: vb2: always set buffer cache sync hints
Message-ID: <X8HaalHqzUYiopAn@jagdpanzerIV.localdomain>
References: <20201127094136.1051071-1-sergey.senozhatsky@gmail.com>
 <0dbfa509-8c82-7470-c18b-24ab5c92dc4b@xs4all.nl>
 <X8ENifLanjYuhF/r@jagdpanzerIV.localdomain>
 <509cc69b-39d7-4b13-f392-ebf25530c8fe@xs4all.nl>
 <X8Eq4V++hRsKuYSF@jagdpanzerIV.localdomain>
 <CAAFQd5D7V8hbdZv_VxAUHUBsbknJsWMaU=h=5j19Z-J8FL27FQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CAAFQd5D7V8hbdZv_VxAUHUBsbknJsWMaU=h=5j19Z-J8FL27FQ@mail.gmail.com>
Precedence: bulk

On (20/11/28 01:50), Tomasz Figa wrote:
> On Sat, Nov 28, 2020 at 1:35 AM Sergey Senozhatsky
> <sergey.senozhatsky@gmail.com> wrote:
> >
> > On (20/11/27 15:56), Hans Verkuil wrote:
> > > Yes.
> > >
> > > BTW, wouldn't it be sufficient to change this code to:
> > >
> > >       if (!q->allow_cache_hints && q->memory != VB2_MEMORY_DMABUF) {
> > >               vb->need_cache_sync_on_prepare = 1;
> > >               vb->need_cache_sync_on_finish = 1;
> > >       }
> >
> > I think it would be sufficient.
> 
> Does it matter at this point if allow_cache_hints is set or not?

That's a good question. I'd say that it'll probably make sense to set
need_cache_sync for as many buffers as possible, regardless the queue
configuration (except for ->memory type), just to stay on the safe side.
I can spin another patch version.

	-ss