[media] v4l2: use __u32 rather than enums in ioctl() structs

V4L2 uses the enum type in IOCTL arguments in IOCTLs that were defined until the use of enum was considered less than ideal. Recently Rémi Denis-Courmont brought up the issue by proposing a patch to convert the enums to unsigned: <URL:http://www.spinics.net/lists/linux-media/msg46167.html> This sparked a long discussion where another solution to the issue was proposed: two sets of IOCTL structures, one with __u32 and the other with enums, and conversion code between the two: <URL:http://www.spinics.net/lists/linux-media/msg47168.html> Both approaches implement a complete solution that resolves the problem. The first one is simple but requires assuming enums and __u32 are the same in size (so we won't break the ABI) while the second one is more complex and less clean but does not require making that assumption. The issue boils down to whether enums are fundamentally different from __u32 or not, and can the former be substituted by the latter. During the discussion it was concluded that the __u32 has the same size as enums on all archs Linux is supported: it has not been shown that replacing those enums in IOCTL arguments would break neither source or binary compatibility. If no such reason is found, just replacing the enums with __u32s is the way to go. This is what this patch does. This patch is slightly different from Remi's first RFC (link above): it uses __u32 instead of unsigned and also changes the arguments of VIDIOC_G_PRIORITY and VIDIOC_S_PRIORITY. Signed-off-by: Rémi Denis-Courmont <remi@remlab.net> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
git-mirror · May 14, 2012 · 6016af8 · 6016af8
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diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml
@@ -543,12 +543,13 @@ and can range from zero to the number of buffers allocated
 with the &VIDIOC-REQBUFS; ioctl (&v4l2-requestbuffers; <structfield>count</structfield>) minus one.</entry>
 	  </row>
 	  <row>
-	    <entry>&v4l2-buf-type;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>type</structfield></entry>
 	    <entry></entry>
 	    <entry>Type of the buffer, same as &v4l2-format;
 <structfield>type</structfield> or &v4l2-requestbuffers;
-<structfield>type</structfield>, set by the application.</entry>
+<structfield>type</structfield>, set by the application. See <xref
+linkend="v4l2-buf-type" /></entry>
 	  </row>
 	  <row>
 	    <entry>__u32</entry>
@@ -568,7 +569,7 @@ refers to an input stream, applications when an output stream.</entry>
 linkend="buffer-flags" />.</entry>
 	  </row>
 	  <row>
-	    <entry>&v4l2-field;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>field</structfield></entry>
 	    <entry></entry>
 	    <entry>Indicates the field order of the image in the
@@ -630,11 +631,12 @@ bandwidth. These devices identify by not enumerating any video
 standards, see <xref linkend="standard" />.</para></entry>
 	  </row>
 	  <row>
-	    <entry>&v4l2-memory;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>memory</structfield></entry>
 	    <entry></entry>
 	    <entry>This field must be set by applications and/or drivers
-in accordance with the selected I/O method.</entry>
+in accordance with the selected I/O method. See <xref linkend="v4l2-memory"
+	    /></entry>
 	  </row>
 	  <row>
 	    <entry>union</entry>

diff --git a/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml b/Documentation/DocBook/media/v4l/vidioc-create-bufs.xml
@@ -94,16 +94,18 @@ information.</para>
 	    <entry>The number of buffers requested or granted.</entry>
 	  </row>
 	  <row>
-	    <entry>&v4l2-memory;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>memory</structfield></entry>
 	    <entry>Applications set this field to
 <constant>V4L2_MEMORY_MMAP</constant> or
-<constant>V4L2_MEMORY_USERPTR</constant>.</entry>
+<constant>V4L2_MEMORY_USERPTR</constant>. See <xref linkend="v4l2-memory"
+/></entry>
 	  </row>
 	  <row>
-	    <entry>&v4l2-format;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>format</structfield></entry>
-	    <entry>Filled in by the application, preserved by the driver.</entry>
+	    <entry>Filled in by the application, preserved by the driver.
+	    See <xref linkend="v4l2-format" />.</entry>
 	  </row>
 	  <row>
 	    <entry>__u32</entry>

diff --git a/Documentation/DocBook/media/v4l/vidioc-cropcap.xml b/Documentation/DocBook/media/v4l/vidioc-cropcap.xml
@@ -65,15 +65,15 @@ output.</para>
 	&cs-str;
 	<tbody valign="top">
 	  <row>
-	    <entry>&v4l2-buf-type;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>type</structfield></entry>
 	    <entry>Type of the data stream, set by the application.
 Only these types are valid here:
 <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>,
 <constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>,
 <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>, and custom (driver
 defined) types with code <constant>V4L2_BUF_TYPE_PRIVATE</constant>
-and higher.</entry>
+and higher. See <xref linkend="v4l2-buf-type" />.</entry>
 	  </row>
 	  <row>
 	    <entry>struct <link linkend="v4l2-rect-crop">v4l2_rect</link></entry>

diff --git a/Documentation/DocBook/media/v4l/vidioc-enum-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-enum-fmt.xml
@@ -71,7 +71,7 @@ the application. This is in no way related to the <structfield>
 pixelformat</structfield> field.</entry>
 	  </row>
 	  <row>
-	    <entry>&v4l2-buf-type;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>type</structfield></entry>
 	    <entry>Type of the data stream, set by the application.
 Only these types are valid here:
@@ -81,7 +81,7 @@ Only these types are valid here:
 <constant>V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE</constant>,
 <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>, and custom (driver
 defined) types with code <constant>V4L2_BUF_TYPE_PRIVATE</constant>
-and higher.</entry>
+and higher. See <xref linkend="v4l2-buf-type" />.</entry>
 	  </row>
 	  <row>
 	    <entry>__u32</entry>

diff --git a/Documentation/DocBook/media/v4l/vidioc-g-crop.xml b/Documentation/DocBook/media/v4l/vidioc-g-crop.xml
@@ -100,14 +100,14 @@ changed and <constant>VIDIOC_S_CROP</constant> returns the
 	&cs-str;
 	<tbody valign="top">
 	  <row>
-	    <entry>&v4l2-buf-type;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>type</structfield></entry>
 	    <entry>Type of the data stream, set by the application.
 Only these types are valid here: <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>,
 <constant>V4L2_BUF_TYPE_VIDEO_OUTPUT</constant>,
 <constant>V4L2_BUF_TYPE_VIDEO_OVERLAY</constant>, and custom (driver
 defined) types with code <constant>V4L2_BUF_TYPE_PRIVATE</constant>
-and higher.</entry>
+and higher. See <xref linkend="v4l2-buf-type" />.</entry>
 	  </row>
 	  <row>
 	    <entry>&v4l2-rect;</entry>

diff --git a/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml b/Documentation/DocBook/media/v4l/vidioc-g-fmt.xml
@@ -116,7 +116,7 @@ this ioctl.</para>
 	<colspec colname="c4" />
 	<tbody valign="top">
 	  <row>
-	    <entry>&v4l2-buf-type;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>type</structfield></entry>
 	    <entry></entry>
 	    <entry>Type of the data stream, see <xref

diff --git a/Documentation/DocBook/media/v4l/vidioc-g-frequency.xml b/Documentation/DocBook/media/v4l/vidioc-g-frequency.xml
@@ -95,14 +95,14 @@ the &v4l2-output; <structfield>modulator</structfield> field and the
 &v4l2-modulator; <structfield>index</structfield> field.</entry>
 	  </row>
 	  <row>
-	    <entry>&v4l2-tuner-type;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>type</structfield></entry>
 	    <entry>The tuner type. This is the same value as in the
-&v4l2-tuner; <structfield>type</structfield> field. The type must be set
+&v4l2-tuner; <structfield>type</structfield> field. See The type must be set
 to <constant>V4L2_TUNER_RADIO</constant> for <filename>/dev/radioX</filename>
 device nodes, and to <constant>V4L2_TUNER_ANALOG_TV</constant>
 for all others. The field is not applicable to modulators, &ie; ignored
-by drivers.</entry>
+by drivers. See <xref linkend="v4l2-tuner-type" /></entry>
 	  </row>
 	  <row>
 	    <entry>__u32</entry>

diff --git a/Documentation/DocBook/media/v4l/vidioc-g-parm.xml b/Documentation/DocBook/media/v4l/vidioc-g-parm.xml
@@ -75,11 +75,12 @@ devices.</para>
 	&cs-ustr;
 	<tbody valign="top">
 	  <row>
-	    <entry>&v4l2-buf-type;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>type</structfield></entry>
 	    <entry></entry>
 	    <entry>The buffer (stream) type, same as &v4l2-format;
-<structfield>type</structfield>, set by the application.</entry>
+<structfield>type</structfield>, set by the application. See <xref
+	    linkend="v4l2-buf-type" /></entry>
 	  </row>
 	  <row>
 	    <entry>union</entry>

diff --git a/Documentation/DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml b/Documentation/DocBook/media/v4l/vidioc-g-sliced-vbi-cap.xml
@@ -148,7 +148,7 @@ using the &VIDIOC-S-FMT; ioctl as described in <xref
 <structfield>service_lines</structfield>[1][0] to zero.</entry>
 	  </row>
 	  <row>
-	    <entry>&v4l2-buf-type;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>type</structfield></entry>
 	    <entry>Type of the data stream, see <xref
 		  linkend="v4l2-buf-type" />. Should be

diff --git a/Documentation/DocBook/media/v4l/vidioc-g-tuner.xml b/Documentation/DocBook/media/v4l/vidioc-g-tuner.xml
@@ -107,7 +107,7 @@ user.<!-- FIXME Video inputs already have a name, the purpose of this
 field is not quite clear.--></para></entry>
 	  </row>
 	  <row>
-	    <entry>&v4l2-tuner-type;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>type</structfield></entry>
 	    <entry spanname="hspan">Type of the tuner, see <xref
 		linkend="v4l2-tuner-type" />.</entry>

diff --git a/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml b/Documentation/DocBook/media/v4l/vidioc-queryctrl.xml
@@ -127,7 +127,7 @@ the first control with a higher ID. Drivers which do not support this
 flag yet always return an &EINVAL;.</entry>
 	  </row>
 	  <row>
-	    <entry>&v4l2-ctrl-type;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>type</structfield></entry>
 	    <entry>Type of control, see <xref
 		linkend="v4l2-ctrl-type" />.</entry>

diff --git a/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml b/Documentation/DocBook/media/v4l/vidioc-reqbufs.xml
@@ -92,18 +92,19 @@ streamoff.--></para>
 	    <entry>The number of buffers requested or granted.</entry>
 	  </row>
 	  <row>
-	    <entry>&v4l2-buf-type;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>type</structfield></entry>
 	    <entry>Type of the stream or buffers, this is the same
 as the &v4l2-format; <structfield>type</structfield> field. See <xref
 		linkend="v4l2-buf-type" /> for valid values.</entry>
 	  </row>
 	  <row>
-	    <entry>&v4l2-memory;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>memory</structfield></entry>
 	    <entry>Applications set this field to
 <constant>V4L2_MEMORY_MMAP</constant> or
-<constant>V4L2_MEMORY_USERPTR</constant>.</entry>
+<constant>V4L2_MEMORY_USERPTR</constant>. See <xref linkend="v4l2-memory"
+/>.</entry>
 	  </row>
 	  <row>
 	    <entry>__u32</entry>

diff --git a/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml b/Documentation/DocBook/media/v4l/vidioc-s-hw-freq-seek.xml
@@ -73,10 +73,11 @@ same value as in the &v4l2-input; <structfield>tuner</structfield>
 field and the &v4l2-tuner; <structfield>index</structfield> field.</entry>
 	  </row>
 	  <row>
-	    <entry>&v4l2-tuner-type;</entry>
+	    <entry>__u32</entry>
 	    <entry><structfield>type</structfield></entry>
 	    <entry>The tuner type. This is the same value as in the
-&v4l2-tuner; <structfield>type</structfield> field.</entry>
+&v4l2-tuner; <structfield>type</structfield> field. See <xref
+	    linkend="v4l2-tuner-type" /></entry>
 	  </row>
 	  <row>
 	    <entry>__u32</entry>

diff --git a/drivers/media/video/v4l2-compat-ioctl32.c b/drivers/media/video/v4l2-compat-ioctl32.c
@@ -37,7 +37,7 @@ struct v4l2_clip32 {
 
 struct v4l2_window32 {
 	struct v4l2_rect        w;
-	enum v4l2_field  	field;
+	__u32		  	field;	/* enum v4l2_field */
 	__u32			chromakey;
 	compat_caddr_t		clips; /* actually struct v4l2_clip32 * */
 	__u32			clipcount;
@@ -147,7 +147,7 @@ static inline int put_v4l2_sliced_vbi_format(struct v4l2_sliced_vbi_format *kp,
 }
 
 struct v4l2_format32 {
-	enum v4l2_buf_type type;
+	__u32	type;	/* enum v4l2_buf_type */
 	union {
 		struct v4l2_pix_format	pix;
 		struct v4l2_pix_format_mplane	pix_mp;
@@ -170,7 +170,7 @@ struct v4l2_format32 {
 struct v4l2_create_buffers32 {
 	__u32			index;
 	__u32			count;
-	enum v4l2_memory        memory;
+	__u32			memory;	/* enum v4l2_memory */
 	struct v4l2_format32	format;
 	__u32			reserved[8];
 };
@@ -311,16 +311,16 @@ struct v4l2_plane32 {
 
 struct v4l2_buffer32 {
 	__u32			index;
-	enum v4l2_buf_type      type;
+	__u32			type;	/* enum v4l2_buf_type */
 	__u32			bytesused;
 	__u32			flags;
-	enum v4l2_field		field;
+	__u32			field;	/* enum v4l2_field */
 	struct compat_timeval	timestamp;
 	struct v4l2_timecode	timecode;
 	__u32			sequence;
 
 	/* memory location */
-	enum v4l2_memory        memory;
+	__u32			memory;	/* enum v4l2_memory */
 	union {
 		__u32           offset;
 		compat_long_t   userptr;