From: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
To: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
devel@driverdev.osuosl.org, linux-arm-kernel@lists.infradead.org,
linux-sunxi@googlegroups.com
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>,
Maxime Ripard <maxime.ripard@bootlin.com>,
Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Chen-Yu Tsai <wens@csie.org>,
Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
Hans Verkuil <hverkuil@xs4all.nl>,
Ezequiel Garcia <ezequiel@collabora.com>,
Tomasz Figa <tfiga@chromium.org>,
Alexandre Courbot <acourbot@chromium.org>,
Nicolas Dufresne <nicolas@ndufresne.ca>,
Boris Brezillon <boris.brezillon@collabora.com>,
Jernej Skrabec <jernej.skrabec@siol.net>,
Jonas Karlman <jonas@kwiboo.se>,
Sakari Ailus <sakari.ailus@linux.intel.com>
Subject: [PATCH v7 1/4] media: v4l2-ctrl: Add a comment on why we zero out compound controls fields
Date: Thu, 25 Jul 2019 20:55:59 +0200 [thread overview]
Message-ID: <20190725185602.22522-2-paul.kocialkowski@bootlin.com> (raw)
In-Reply-To: <20190725185602.22522-1-paul.kocialkowski@bootlin.com>
Since it's not necessarily very explicit why we need to zero some fields
in std_validate_compound, add a comment before the function to explain
why, which should help as a reminder.
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
---
drivers/media/v4l2-core/v4l2-ctrls.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/media/v4l2-core/v4l2-ctrls.c b/drivers/media/v4l2-core/v4l2-ctrls.c
index 76fa2db0e8fb..cd1ae016706f 100644
--- a/drivers/media/v4l2-core/v4l2-ctrls.c
+++ b/drivers/media/v4l2-core/v4l2-ctrls.c
@@ -1645,6 +1645,10 @@ static void std_log(const struct v4l2_ctrl *ctrl)
#define zero_padding(s) \
memset(&(s).padding, 0, sizeof((s).padding))
+/*
+ * Compound controls validation requires setting unused fields/flags to zero
+ * in order to properly detect unchanged controls with std_equal's memcmp.
+ */
static int std_validate_compound(const struct v4l2_ctrl *ctrl, u32 idx,
union v4l2_ctrl_ptr ptr)
{
--
2.22.0
next prev parent reply other threads:[~2019-07-25 18:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-25 18:55 [PATCH v7 0/4] HEVC/H.265 stateless support for V4L2 and Cedrus Paul Kocialkowski
2019-07-25 18:55 ` Paul Kocialkowski [this message]
2019-07-25 18:56 ` [PATCH v7 2/4] media: v4l: Add definitions for the HEVC slice controls Paul Kocialkowski
2019-07-25 18:56 ` [PATCH v7 3/4] media: pixfmt: Document the HEVC slice pixel format Paul Kocialkowski
2019-07-25 18:56 ` [PATCH v7 4/4] media: cedrus: Add HEVC/H.265 decoding support Paul Kocialkowski
2019-07-26 8:33 ` [PATCH v7 0/4] HEVC/H.265 stateless support for V4L2 and Cedrus Hans Verkuil
2019-07-27 9:57 ` Paul Kocialkowski
2019-07-30 7:27 ` Hans Verkuil
2019-07-31 12:43 ` Paul Kocialkowski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190725185602.22522-2-paul.kocialkowski@bootlin.com \
--to=paul.kocialkowski@bootlin.com \
--cc=acourbot@chromium.org \
--cc=boris.brezillon@collabora.com \
--cc=devel@driverdev.osuosl.org \
--cc=ezequiel@collabora.com \
--cc=gregkh@linuxfoundation.org \
--cc=hverkuil@xs4all.nl \
--cc=jernej.skrabec@siol.net \
--cc=jonas@kwiboo.se \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=linux-sunxi@googlegroups.com \
--cc=maxime.ripard@bootlin.com \
--cc=mchehab@kernel.org \
--cc=nicolas@ndufresne.ca \
--cc=sakari.ailus@linux.intel.com \
--cc=tfiga@chromium.org \
--cc=thomas.petazzoni@bootlin.com \
--cc=wens@csie.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).