[vlc-devel] [PATCH] v4l/v4l2: add mmap() fall back for nommu systems

[Mike Frysinger]

On Linux no-mmu systems, getting a shared mapping often results in failure.
If the mmap() in v4l failed with MAP_SHARED, then fall back to MAP_PRIVATE.

Signed-off-by: Mike Frysinger <vapier at gentoo.org>
---
 modules/access/v4l.c  |   22 +++++++++++++++++-----
 modules/access/v4l2.c |    9 +++++++--
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/modules/access/v4l.c b/modules/access/v4l.c
index 69eb305..f9d5841 100644
--- a/modules/access/v4l.c
+++ b/modules/access/v4l.c
@@ -1113,8 +1113,14 @@ static int OpenVideoDev( demux_t *p_demux, char *psz_device )
                 PROT_READ | PROT_WRITE, MAP_SHARED, i_fd, 0 );
         if( p_sys->p_video_mmap == MAP_FAILED )
         {
-            msg_Err( p_demux, "mmap failed" );
-            goto vdev_failed;
+            p_sys->p_video_mmap = mmap( 0,
+                    p_sys->mjpeg_buffers.size * p_sys->mjpeg_buffers.count,
+                    PROT_READ | PROT_WRITE, MAP_PRIVATE, i_fd, 0 );
+            if( p_sys->p_video_mmap == MAP_FAILED )
+            {
+                msg_Err( p_demux, "mmap failed" );
+                goto vdev_failed;
+            }
         }
 
         p_sys->i_fourcc  = VLC_FOURCC( 'm','j','p','g' );
@@ -1165,9 +1171,15 @@ static int OpenVideoDev( demux_t *p_demux, char *psz_device )
                                     i_fd, 0 );
         if( p_sys->p_video_mmap == MAP_FAILED )
         {
-            /* FIXME -> normal read */
-            msg_Err( p_demux, "mmap failed" );
-            goto vdev_failed;
+            p_sys->p_video_mmap = mmap( 0, p_sys->vid_mbuf.size,
+                                        PROT_READ|PROT_WRITE, MAP_PRIVATE,
+                                        i_fd, 0 );
+            if( p_sys->p_video_mmap == MAP_FAILED )
+            {
+                /* FIXME -> normal read */
+                msg_Err( p_demux, "mmap failed" );
+                goto vdev_failed;
+            }
         }
 
         /* init grabbing */
diff --git a/modules/access/v4l2.c b/modules/access/v4l2.c
index e4fb38a..039aeca 100644
--- a/modules/access/v4l2.c
+++ b/modules/access/v4l2.c
@@ -1428,8 +1428,13 @@ static int InitMmap( demux_t *p_demux, int i_fd )
 
         if( p_sys->p_buffers[p_sys->i_nbuffers].start == MAP_FAILED )
         {
-            msg_Err( p_demux, "mmap failed (%m)" );
-            goto open_failed;
+            p_sys->p_buffers[p_sys->i_nbuffers].start =
+                v4l2_mmap( NULL, buf.length, PROT_READ | PROT_WRITE, MAP_PRIVATE, i_fd, buf.m.offset );
+            if( p_sys->p_buffers[p_sys->i_nbuffers].start == MAP_FAILED )
+            {
+                msg_Err( p_demux, "mmap failed (%m)" );
+                goto open_failed;
+            }
         }
     }
 
-- 
1.6.0.6