Obsolete --v4l2-io and auto-detect the correct setting

For the time being, mmap() is used if supported, otherwise read() if
supported, otherwise fail. This makes the user pointer method dead
code. It might make sense to revive it on capable device drivers to
support zero copy, but until then that method is no better than mmap().

modules/access/v4l2.c

@@ -93,9 +93,6 @@ static void AccessClose( vlc_object_t * );
 #define AUDIO_INPUT_TEXT N_( "Audio input" )
 #define AUDIO_INPUT_LONGTEXT N_( \
     "Audio input of the card to use (see debug)." )
-#define IOMETHOD_TEXT N_( "IO Method" )
-#define IOMETHOD_LONGTEXT N_( \
-    "IO Method (READ, MMAP, USERPTR)." )
 #define WIDTH_TEXT N_( "Width" )
 #define WIDTH_LONGTEXT N_( \
     "Force width (-1 for autodetect, 0 for driver default)." )
@@ -216,8 +213,7 @@ static void AccessClose( vlc_object_t * );
 #define ASPECT_LONGTEXT N_("Define input picture aspect-ratio to use. Default is 4:3" )
 
 typedef enum {
-    IO_METHOD_AUTO,
-    IO_METHOD_READ,
+    IO_METHOD_READ=1,
     IO_METHOD_MMAP,
     IO_METHOD_USERPTR,
 } io_method;
@@ -278,11 +274,6 @@ static const char *const standards_user[] = { N_("Undefined"), N_("All"),
     "ATSC 8-VSB",     "ATSC 16-VSB",
 };
 
-static const int i_iomethod_list[] =
-    { IO_METHOD_AUTO, IO_METHOD_READ, IO_METHOD_MMAP, IO_METHOD_USERPTR };
-static const char *const psz_iomethod_list_text[] =
-    { N_("AUTO"), N_("READ"), N_("MMAP"),  N_("USERPTR") };
-
 static const int i_tuner_audio_modes_list[] = {
       -1, V4L2_TUNER_MODE_MONO, V4L2_TUNER_MODE_STEREO,
       V4L2_TUNER_MODE_LANG1, V4L2_TUNER_MODE_LANG2,
@@ -329,9 +320,7 @@ vlc_module_begin ()
     add_integer( CFG_PREFIX "audio-input", 0, AUDIO_INPUT_TEXT,
                  AUDIO_INPUT_LONGTEXT, true )
         change_integer_range( 0, 0xFFFFFFFE )
-    add_integer( CFG_PREFIX "io", IO_METHOD_AUTO, IOMETHOD_TEXT,
-                 IOMETHOD_LONGTEXT, true )
-        change_integer_list( i_iomethod_list, psz_iomethod_list_text )
+    add_obsolete_integer( CFG_PREFIX "io" ) /* since 1.2.0 */
     add_integer( CFG_PREFIX "width", DEFAULT_WIDTH, WIDTH_TEXT,
                 WIDTH_LONGTEXT, true )
     add_integer( CFG_PREFIX "height", DEFAULT_HEIGHT, HEIGHT_TEXT,
@@ -573,8 +562,6 @@ struct demux_sys_t
     /* Video */
     io_method io;
 
-    struct v4l2_capability dev_cap;
-
     uint32_t i_input;
     struct v4l2_input *p_inputs;
     unsigned i_selected_input;
@@ -702,8 +689,6 @@ static void GetV4L2Params( demux_sys_t *p_sys, vlc_object_t *p_obj )
     p_sys->i_selected_audio_input =
         var_CreateGetInteger( p_obj, "v4l2-audio-input" );
 
-    p_sys->io = var_CreateGetInteger( p_obj, "v4l2-io" );
-
     p_sys->i_width = var_CreateGetInteger( p_obj, "v4l2-width" );
     p_sys->i_height = var_CreateGetInteger( p_obj, "v4l2-height" );
 
@@ -803,34 +788,6 @@ static void ParseMRL( demux_sys_t *p_sys, char *psz_path, vlc_object_t *p_obj )
                 p_sys->f_fps = us_strtof( psz_parser + strlen( "fps=" ),
                                           &psz_parser );
             }
-            else if( !strncmp( psz_parser, "io=", strlen( "io=" ) ) )
-            {
-                psz_parser += strlen( "io=" );
-                if( !strncmp( psz_parser, "read", strlen( "read" ) ) )
-                {
-                    p_sys->io = IO_METHOD_READ;
-                    psz_parser += strlen( "read" );
-                }
-                else if( !strncmp( psz_parser, "mmap", strlen( "mmap" ) ) )
-                {
-                    p_sys->io = IO_METHOD_MMAP;
-                    psz_parser += strlen( "mmap" );
-                }
-                else if( !strncmp( psz_parser, "userptr", strlen( "userptr" ) ) )
-                {
-                    p_sys->io = IO_METHOD_USERPTR;
-                    psz_parser += strlen( "userptr" );
-                }
-                else if( !strncmp( psz_parser, "auto", strlen( "auto" ) ) )
-                {
-                    p_sys->io = IO_METHOD_AUTO;
-                    psz_parser += strlen( "auto" );
-                }
-                else
-                {
-                    p_sys->io = strtol( psz_parser, &psz_parser, 0 );
-                }
-            }
             else if( !strncmp( psz_parser, "width=",
                                strlen( "width=" ) ) )
             {
@@ -1032,9 +989,6 @@ static void DemuxClose( vlc_object_t *p_this )
             }
 
             break;
-
-        default:
-            break;
         }
     }
 
@@ -1062,9 +1016,6 @@ static void DemuxClose( vlc_object_t *p_this )
                free( p_sys->p_buffers[i].start );
             }
             break;
-
-        default:
-            break;
         }
         free( p_sys->p_buffers );
     }
@@ -1441,9 +1392,6 @@ static block_t* GrabVideo( vlc_object_t *p_demux, demux_sys_t *p_sys )
         }
 
         break;
-
-    default:
-        return NULL;
     }
 
     /* Timestamp */
@@ -1920,36 +1868,6 @@ static int OpenVideoDev( vlc_object_t *p_obj, demux_sys_t *p_sys, bool b_demux )
                  b_demux );
     SetAvailControlsByString( p_obj, p_sys, i_fd );
 
-    /* Verify device support for the various IO methods */
-    switch( p_sys->io )
-    {
-        case IO_METHOD_READ:
-            if( !(p_sys->dev_cap.capabilities & V4L2_CAP_READWRITE) )
-            {
-                msg_Err( p_obj, "device does not support read i/o" );
-                goto error;
-            }
-            msg_Dbg( p_obj, "using read I/O" );
-            break;
-
-        case IO_METHOD_MMAP:
-        case IO_METHOD_USERPTR:
-            if( !(p_sys->dev_cap.capabilities & V4L2_CAP_STREAMING) )
-            {
-                msg_Err( p_obj, "device does not support streaming I/O" );
-                goto error;
-            }
-            if( p_sys->io == IO_METHOD_MMAP )
-                msg_Dbg( p_obj, "using streaming I/O (mmap)" );
-            else
-                msg_Dbg( p_obj, "using streaming I/O (userptr)" );
-            break;
-
-        default:
-            msg_Err( p_obj, "I/O method not supported" );
-            goto error;
-    }
-
     /* Reset Cropping */
     memset( &cropcap, 0, sizeof(cropcap) );
     cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
@@ -2242,8 +2160,6 @@ static int OpenVideoDev( vlc_object_t *p_obj, demux_sys_t *p_sys, bool b_demux )
         if( InitUserP( p_obj, p_sys, i_fd, fmt.fmt.pix.sizeimage ) )
             goto error;
         break;
-    default:
-        assert(0);
     }
 
     if( b_demux )
@@ -2326,8 +2242,6 @@ static int OpenVideoDev( vlc_object_t *p_obj, demux_sys_t *p_sys, bool b_demux )
             goto error;
         }
         break;
-    default:
-        assert(0);
     }
 
     /* report fps */
@@ -2373,65 +2287,57 @@ static bool ProbeVideoDev( vlc_object_t *p_obj, demux_sys_t *p_sys,
 #endif
 
     /* Get device capabilites */
+    struct v4l2_capability cap;
 
-    if( v4l2_ioctl( i_fd, VIDIOC_QUERYCAP, &p_sys->dev_cap ) < 0 )
+    if( v4l2_ioctl( i_fd, VIDIOC_QUERYCAP, &cap ) < 0 )
     {
         msg_Err( p_obj, "cannot get video capabilities: %m" );
         goto error;
     }
 
-    msg_Dbg( p_obj, "V4L2 device: %s using driver: %s (version: %u.%u.%u) on %s",
-                            p_sys->dev_cap.card,
-                            p_sys->dev_cap.driver,
-                            (p_sys->dev_cap.version >> 16) & 0xFF,
-                            (p_sys->dev_cap.version >> 8) & 0xFF,
-                            p_sys->dev_cap.version & 0xFF,
-                            p_sys->dev_cap.bus_info );
-
-    msg_Dbg( p_obj, "the device has the capabilities: (%c) Video Capture, "
-                                                       "(%c) Audio, "
-                                                       "(%c) Tuner, "
-                                                       "(%c) Radio",
-             ( p_sys->dev_cap.capabilities & V4L2_CAP_VIDEO_CAPTURE  ? 'X':' '),
-             ( p_sys->dev_cap.capabilities & V4L2_CAP_AUDIO  ? 'X':' '),
-             ( p_sys->dev_cap.capabilities & V4L2_CAP_TUNER  ? 'X':' '),
-             ( p_sys->dev_cap.capabilities & V4L2_CAP_RADIO  ? 'X':' ') );
-
-    msg_Dbg( p_obj, "supported I/O methods are: (%c) Read/Write, "
-                                                 "(%c) Streaming, "
-                                                 "(%c) Asynchronous",
-            ( p_sys->dev_cap.capabilities & V4L2_CAP_READWRITE ? 'X':' ' ),
-            ( p_sys->dev_cap.capabilities & V4L2_CAP_STREAMING ? 'X':' ' ),
-            ( p_sys->dev_cap.capabilities & V4L2_CAP_ASYNCIO ? 'X':' ' ) );
-
-    if( p_sys->io == IO_METHOD_AUTO )
-    {
-        if( p_sys->dev_cap.capabilities & V4L2_CAP_STREAMING )
+    msg_Dbg( p_obj, "device %s using driver %s (version %u.%u.%u) on %s",
+            cap.card, cap.driver, (cap.version >> 16) & 0xFF,
+            (cap.version >> 8) & 0xFF, cap.version & 0xFF, cap.bus_info );
+    msg_Dbg( p_obj, "the device has the capabilities:"
+             " (%c) Video Capture, (%c) Audio, (%c) Tuner, (%c) Radio",
+             ( cap.capabilities & V4L2_CAP_VIDEO_CAPTURE  ? 'X':' '),
+             ( cap.capabilities & V4L2_CAP_AUDIO  ? 'X':' '),
+             ( cap.capabilities & V4L2_CAP_TUNER  ? 'X':' '),
+             ( cap.capabilities & V4L2_CAP_RADIO  ? 'X':' ') );
+    msg_Dbg( p_obj, "supported I/O methods are:"
+             " (%c) Read/Write, (%c) Streaming, (%c) Asynchronous",
+            ( cap.capabilities & V4L2_CAP_READWRITE ? 'X':' ' ),
+            ( cap.capabilities & V4L2_CAP_STREAMING ? 'X':' ' ),
+            ( cap.capabilities & V4L2_CAP_ASYNCIO ? 'X':' ' ) );
+
+    if( cap.capabilities & V4L2_CAP_STREAMING )
         p_sys->io = IO_METHOD_MMAP;
-        else if( p_sys->dev_cap.capabilities & V4L2_CAP_READWRITE )
+    else if( cap.capabilities & V4L2_CAP_READWRITE )
         p_sys->io = IO_METHOD_READ;
     else
-            msg_Err( p_obj, "No known I/O method supported" );
+    {
+        msg_Err( p_obj, "no supported I/O method" );
+        goto error;
     }
 
-    if( p_sys->dev_cap.capabilities & V4L2_CAP_RDS_CAPTURE )
+    if( cap.capabilities & V4L2_CAP_RDS_CAPTURE )
         msg_Dbg( p_obj, "device supports RDS" );
 
 #ifdef V4L2_CAP_HW_FREQ_SEEK
-    if( p_sys->dev_cap.capabilities & V4L2_CAP_HW_FREQ_SEEK )
+    if( cap.capabilities & V4L2_CAP_HW_FREQ_SEEK )
         msg_Dbg( p_obj, "device supports hardware frequency seeking" );
 #endif
-    if( p_sys->dev_cap.capabilities & V4L2_CAP_VBI_CAPTURE )
+    if( cap.capabilities & V4L2_CAP_VBI_CAPTURE )
         msg_Dbg( p_obj, "device supports raw VBI capture" );
 
-    if( p_sys->dev_cap.capabilities & V4L2_CAP_SLICED_VBI_CAPTURE )
+    if( cap.capabilities & V4L2_CAP_SLICED_VBI_CAPTURE )
         msg_Dbg( p_obj, "device supports sliced VBI capture" );
 
     /* Now, enumerate all the video inputs. This is useless at the moment
        since we have no way to present that info to the user except with
        debug messages */
 
-    if( p_sys->dev_cap.capabilities & V4L2_CAP_VIDEO_CAPTURE )
+    if( cap.capabilities & V4L2_CAP_VIDEO_CAPTURE )
     {
         struct v4l2_input t_input;
         memset( &t_input, 0, sizeof(t_input) );
@@ -2475,7 +2381,7 @@ static bool ProbeVideoDev( vlc_object_t *p_obj, demux_sys_t *p_sys,
     }
 
     /* Probe audio inputs */
-    if( p_sys->dev_cap.capabilities & V4L2_CAP_AUDIO )
+    if( cap.capabilities & V4L2_CAP_AUDIO )
     {
         while( p_sys->i_audio < 32 &&
                v4l2_ioctl( i_fd, VIDIOC_S_AUDIO, &p_sys->p_audios[p_sys->i_audio] ) >= 0 )
@@ -2502,7 +2408,7 @@ static bool ProbeVideoDev( vlc_object_t *p_obj, demux_sys_t *p_sys,
     }
 
     /* List tuner caps */
-    if( p_sys->dev_cap.capabilities & V4L2_CAP_TUNER )
+    if( cap.capabilities & V4L2_CAP_TUNER )
     {
         struct v4l2_tuner tuner;
         memset( &tuner, 0, sizeof(tuner) );
@@ -2563,7 +2469,7 @@ static bool ProbeVideoDev( vlc_object_t *p_obj, demux_sys_t *p_sys,
     }
 
     /* Probe for available chromas */
-    if( p_sys->dev_cap.capabilities & V4L2_CAP_VIDEO_CAPTURE )
+    if( cap.capabilities & V4L2_CAP_VIDEO_CAPTURE )
     {
         struct v4l2_fmtdesc codec;