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From: Chen-Yu Tsai <wenst@chromium.org>
To: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Tomasz Figa <tfiga@chromium.org>,
	Hans Verkuil <hverkuil-cisco@xs4all.nl>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Dafna Hirschfeld <dafna.hirschfeld@collabora.com>,
	Ricardo Ribalda <ribalda@chromium.org>,
	Christoph Hellwig <hch@lst.de>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCHv6 2/8] videobuf2: inverse buffer cache_hints flags
Date: Tue, 28 Sep 2021 14:05:36 +0800	[thread overview]
Message-ID: <YVKwsMDU6eNO1X0u@google.com> (raw)
In-Reply-To: <20210909112430.61243-3-senozhatsky@chromium.org>

Hi,

On Thu, Sep 09, 2021 at 08:24:24PM +0900, Sergey Senozhatsky wrote:
> It would be less error prone if the default cache hints value
> (we kzalloc() structs, so it's zeroed out by default) would be
> to "always sync/flush" caches. Inverse and rename cache hints
> flags.
> 
> Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> ---
>  .../media/common/videobuf2/videobuf2-core.c   | 31 ++++++-------------
>  .../media/common/videobuf2/videobuf2-v4l2.c   | 17 +++-------
>  include/media/videobuf2-core.h                | 12 +++----
>  3 files changed, 21 insertions(+), 39 deletions(-)
> 
> diff --git a/drivers/media/common/videobuf2/videobuf2-core.c b/drivers/media/common/videobuf2/videobuf2-core.c
> index c4ff356da600..9d57df348b5f 100644
> --- a/drivers/media/common/videobuf2/videobuf2-core.c
> +++ b/drivers/media/common/videobuf2/videobuf2-core.c

[...]

> @@ -415,17 +415,6 @@ static int __vb2_queue_alloc(struct vb2_queue *q, enum vb2_memory memory,
>  		vb->index = q->num_buffers + buffer;
>  		vb->type = q->type;
>  		vb->memory = memory;
> -		/*
> -		 * We need to set these flags here so that the videobuf2 core
> -		 * will call ->prepare()/->finish() cache sync/flush on vb2
> -		 * buffers when appropriate. However, we can avoid explicit
> -		 * ->prepare() and ->finish() cache sync for DMABUF buffers,
> -		 * because DMA exporter takes care of it.
> -		 */
> -		if (q->memory != VB2_MEMORY_DMABUF) {
> -			vb->need_cache_sync_on_prepare = 1;
> -			vb->need_cache_sync_on_finish = 1;
> -		}

This hunk seems odd. It's not inverting the logic but just removing
the block wholesale. The end result is different. This seems to be fixed
in a following patch, but the change here doesn't match what the commit
log says.

ChenYu

  reply	other threads:[~2021-09-28  6:09 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-09 11:24 [PATCHv6 0/8] videobuf2: support new noncontiguous DMA API Sergey Senozhatsky
2021-09-09 11:24 ` [PATCHv6 1/8] videobuf2: rework vb2_mem_ops API Sergey Senozhatsky
2021-09-09 11:24 ` [PATCHv6 2/8] videobuf2: inverse buffer cache_hints flags Sergey Senozhatsky
2021-09-28  6:05   ` Chen-Yu Tsai [this message]
2021-09-09 11:24 ` [PATCHv6 3/8] videobuf2: split buffer cache_hints initialisation Sergey Senozhatsky
2021-09-09 11:24 ` [PATCHv6 4/8] videobuf2: move cache_hints handling to allocators Sergey Senozhatsky
2021-09-09 11:24 ` [PATCHv6 5/8] videobuf2: add V4L2_MEMORY_FLAG_NON_COHERENT flag Sergey Senozhatsky
2021-09-09 11:24 ` [PATCHv6 6/8] videobuf2: add queue memory coherency parameter Sergey Senozhatsky
2021-09-09 11:24 ` [PATCHv6 7/8] videobuf2: handle V4L2_MEMORY_FLAG_NON_COHERENT flag Sergey Senozhatsky
2021-09-28  4:50   ` Sergey Senozhatsky
2021-09-09 11:24 ` [PATCHv6 8/8] videobuf2: handle non-contiguous DMA allocations Sergey Senozhatsky
2021-09-10 10:00 ` [PATCHv6 0/8] videobuf2: support new noncontiguous DMA API Tomasz Figa

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