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From: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>, mchehab@kernel.org
Cc: linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Subject: [PATCH 5/6] media: vsp1: Document max_width restriction on UDS
Date: Fri, 31 Aug 2018 15:40:43 +0100	[thread overview]
Message-ID: <20180831144044.31713-6-kieran.bingham+renesas@ideasonboard.com> (raw)
In-Reply-To: <20180831144044.31713-1-kieran.bingham+renesas@ideasonboard.com>

The UDS is currently restricted based on a partition size of 256 pixels.
Document the actual restrictions, but don't increase the implementation.

The extended partition algorithm may later choose to utilise a larger
partition size to support overlapping partitions.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
---
 drivers/media/platform/vsp1/vsp1_uds.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/media/platform/vsp1/vsp1_uds.c b/drivers/media/platform/vsp1/vsp1_uds.c
index c20c84b54936..7c11651db5d4 100644
--- a/drivers/media/platform/vsp1/vsp1_uds.c
+++ b/drivers/media/platform/vsp1/vsp1_uds.c
@@ -342,6 +342,14 @@ static unsigned int uds_max_width(struct vsp1_entity *entity,
 					    UDS_PAD_SOURCE);
 	hscale = output->width / input->width;
 
+	/*
+	 * The maximum width of the UDS is 304 pixels. These are input pixels
+	 * in the event of up-scaling, and output pixels in the event of
+	 * downscaling.
+	 *
+	 * To support the current parition algorithm, we clamp at units of 256.
+	 */
+
 	if (hscale <= 2)
 		return 256;
 	else if (hscale <= 4)
-- 
2.17.1


  parent reply	other threads:[~2018-08-31 14:40 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-31 14:40 [PATCH 0/6] VSP1 Updates Kieran Bingham
2018-08-31 14:40 ` [PATCH 1/6] media: vsp1: Remove artificial pixel limitation Kieran Bingham
2018-09-14 10:23   ` Laurent Pinchart
2018-09-14 10:47     ` Laurent Pinchart
2018-09-14 10:51       ` Kieran Bingham
2018-08-31 14:40 ` [PATCH 2/6] media: vsp1: Correct the pitch on multiplanar formats Kieran Bingham
2018-09-14 10:25   ` Laurent Pinchart
2018-09-14 10:59     ` Kieran Bingham
2018-08-31 14:40 ` [PATCH 3/6] media: vsp1: Implement partition algorithm restrictions Kieran Bingham
2018-09-14 10:38   ` Laurent Pinchart
2018-08-31 14:40 ` [PATCH 4/6] media: vsp1: Document max_width restriction on SRU Kieran Bingham
2018-09-14 10:42   ` Laurent Pinchart
2018-08-31 14:40 ` Kieran Bingham [this message]
2018-08-31 14:40 ` [PATCH 6/6] media: vsp1: use periods at the end of comment sentences Kieran Bingham
2018-09-14 10:46   ` Laurent Pinchart

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