From 03939db7cb0e4b430043d2a6ff542909a91e544a Mon Sep 17 00:00:00 2001 From: Kieran Bingham Date: Fri, 14 Sep 2018 10:26:52 -0400 Subject: media: vsp1: Document max_width restriction on UDS 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 which will improve the quality of the output images. Signed-off-by: Kieran Bingham Signed-off-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- drivers/media/platform/vsp1/vsp1_uds.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers/media/platform/vsp1') diff --git a/drivers/media/platform/vsp1/vsp1_uds.c b/drivers/media/platform/vsp1/vsp1_uds.c index 75c613050151..27012af973b2 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 overlapping partition windows we clamp at units of 256 and + * the remaining pixels are reserved. + */ if (hscale <= 2) return 256; else if (hscale <= 4) -- cgit v1.2.3-55-g7522