From: Hui Fang <hui.fang@nxp.com>
To: Tomasz Figa <tfiga@chromium.org>
Cc: Anle Pan <anle.pan@nxp.com>,
"m.szyprowski@samsung.com" <m.szyprowski@samsung.com>,
"mchehab@kernel.org" <mchehab@kernel.org>,
"linux-media@vger.kernel.org" <linux-media@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Jindong Yue <jindong.yue@nxp.com>,
Xuegang Liu <xuegang.liu@nxp.com>
Subject: RE: [EXT] Re: [PATCH] media: videobuf2-dma-sg: limit the sg segment size
Date: Mon, 4 Sep 2023 07:10:08 +0000 [thread overview]
Message-ID: <DB9PR04MB928460023FB3CCCBC3EACE1487E9A@DB9PR04MB9284.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <CAAFQd5DYxwX+JdXQ_-ba5B9y+gyWPjvUpCBnKM1zz1W2EkO_vA@mail.gmail.com>
On Wed, Aug 30, 2023 at 6:20 PM Tomasz Figa <tfiga@chromium.org> wrote:
> On Wed, Aug 30, 2023 at 5:50 PM Hui Fang <hui.fang@nxp.com> wrote:
......
> > I wonder if only NXP met the "swiotlb buffer full" issue. In theory,
> > when format is YUYV, those resolutions no greater than 320x240 (153600
> > bytes, which less than the max mapping size 256K ) can't meet the issue.
> > But resolutions no less than 640x480 (307200 bytes), may have chances
> > to trigger the issue.
>
> I think a combination of a device that can support scatter-gather, but requires
> swiotlb is kind of rare. Most drivers would require a single contiguous DMA
> address (and thus use videobuf2-dma-contig) and physical discontinuity would
> be handled by an IOMMU (transparently to vb2).
>
> I guess one thing to ask you about your specific setup is whether it's expected
> that the swiotlb ends up being used at all?
Yes, the swiotlb ends up being used. We met the issue when bring up
DeviceAsWebCam (android-14 new feature, android device works as a usb camera).
BRs,
Fang Hui
next prev parent reply other threads:[~2023-09-04 7:10 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-28 7:54 [PATCH] media: videobuf2-dma-sg: limit the sg segment size Anle Pan
2023-08-29 10:03 ` Tomasz Figa
2023-08-29 11:14 ` Robin Murphy
2023-08-29 15:04 ` Christoph Hellwig
2023-08-30 3:47 ` Tomasz Figa
2023-08-30 14:33 ` Christoph Hellwig
2023-08-30 16:43 ` Jason Gunthorpe
2023-08-31 12:35 ` Christoph Hellwig
2023-08-31 15:32 ` Jason Gunthorpe
2023-09-01 6:10 ` Christoph Hellwig
2023-09-01 14:26 ` Jason Gunthorpe
[not found] ` <DB9PR04MB92841D8BC1122D5A4210F78987E6A@DB9PR04MB9284.eurprd04.prod.outlook.com>
2023-08-30 13:41 ` [EXT] " Robin Murphy
2023-08-30 3:59 ` Tomasz Figa
2023-09-06 8:52 ` Hans Verkuil
2023-09-06 9:26 ` Tomasz Figa
2023-09-06 9:43 ` Hans Verkuil
2023-08-30 8:50 ` Hui Fang
2023-08-30 9:28 ` Tomasz Figa
2023-09-04 7:10 ` Hui Fang [this message]
2023-09-05 3:43 ` [EXT] " Tomasz Figa
2023-09-06 8:16 ` Hui Fang
2023-09-06 9:28 ` Tomasz Figa
2023-09-11 6:13 ` Hui Fang
2023-09-12 2:22 ` Tomasz Figa
2023-09-12 7:01 ` Hui Fang
2023-09-12 7:10 ` Tomasz Figa
2023-09-12 7:43 ` Hui Fang
2023-09-12 7:51 ` Tomasz Figa
2023-09-13 9:13 ` Hui Fang
2023-09-13 9:44 ` Tomasz Figa
2023-09-13 13:16 ` Hui Fang
2023-09-18 2:28 ` Hui Fang
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