Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754801AbdGVVVy (ORCPT ); Sat, 22 Jul 2017 17:21:54 -0400 Received: from mail-pg0-f68.google.com ([74.125.83.68]:34005 "EHLO mail-pg0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752342AbdGVVVw (ORCPT ); Sat, 22 Jul 2017 17:21:52 -0400 From: Steve Longerbeam X-Google-Original-From: Steve Longerbeam To: Philipp Zabel , Mauro Carvalho Chehab , Greg Kroah-Hartman Cc: linux-media@vger.kernel.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, Steve Longerbeam Subject: [PATCH] media: imx: prpencvf: enable double write reduction Date: Sat, 22 Jul 2017 14:21:41 -0700 Message-Id: <1500758501-5394-1-git-send-email-steve_longerbeam@mentor.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1112 Lines: 33 For the write channels with 4:2:0 subsampled YUV formats, avoid chroma overdraw by only writing chroma for even lines. Reduces necessary write memory bandwidth by at least 25% (more with rotation enabled). Signed-off-by: Steve Longerbeam --- drivers/staging/media/imx/imx-ic-prpencvf.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/staging/media/imx/imx-ic-prpencvf.c b/drivers/staging/media/imx/imx-ic-prpencvf.c index ed363fe..42c5045 100644 --- a/drivers/staging/media/imx/imx-ic-prpencvf.c +++ b/drivers/staging/media/imx/imx-ic-prpencvf.c @@ -374,6 +374,17 @@ static int prp_setup_channel(struct prp_priv *priv, image.phys0 = addr0; image.phys1 = addr1; + if (channel == priv->out_ch || channel == priv->rot_out_ch) { + switch (image.pix.pixelformat) { + case V4L2_PIX_FMT_YUV420: + case V4L2_PIX_FMT_YVU420: + case V4L2_PIX_FMT_NV12: + /* Skip writing U and V components to odd rows */ + ipu_cpmem_skip_odd_chroma_rows(channel); + break; + } + } + ret = ipu_cpmem_set_image(channel, &image); if (ret) return ret; -- 2.7.4