stream/tvi_v4l[2]: fix calculation of free RAM for buffers

Do a proper calculation of free RAM to be used as V4L buffers.
The code uses sysinfo to query the available RAM, however it used
ancient form available in some early development 2.3.x kernels.
Newer form reports the size in memory units (usually same as page size),
as result the code would fall back on 2 buffers even on multi GB system.

The commit does: Improve the check in configure to ensure that we
do use sysinfo struct with present mem_unit. Use free RAM instead of
total RAM (to avoid swapping). Tweak memory constants and simplify code.

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@33732 b3059339-0415-0410-9bf9-f77b7e298cf2

3 files changed, 11 insertions, 17 deletions

diff --git a/configure b/configure
index 8d86901f2f..59b9f6d9e0 100755
--- a/configure
+++ b/configure
@@ -3551,7 +3551,7 @@ fi #if sunos
 
 echocheck "sys/sysinfo.h"
 _sys_sysinfo=no
-statement_check sys/sysinfo.h 'struct sysinfo s_info; sysinfo(&s_info)' && _sys_sysinfo=yes
+statement_check sys/sysinfo.h 'struct sysinfo s_info; s_info.mem_unit=0; sysinfo(&s_info)' && _sys_sysinfo=yes
 if test "$_sys_sysinfo" = yes ; then
   def_sys_sysinfo_h='#define HAVE_SYS_SYSINFO_H 1'
 else
diff --git a/stream/tvi_v4l.c b/stream/tvi_v4l.c
index bbf290eeaf..31f767850b 100644
--- a/stream/tvi_v4l.c
+++ b/stream/tvi_v4l.c
@@ -760,7 +760,8 @@ static int uninit(priv_t *priv)
 
 static int get_capture_buffer_size(priv_t *priv)
 {
-    int bufsize, cnt;
+    uint64_t bufsize;
+    int cnt;
 
     if (priv->tv_param->buffer_size >= 0) {
         bufsize = priv->tv_param->buffer_size*1024*1024;
@@ -769,14 +770,10 @@ static int get_capture_buffer_size(priv_t *priv)
         struct sysinfo si;
 
         sysinfo(&si);
-        if (si.totalram<2*1024*1024) {
-            bufsize = 1024*1024;
-        } else {
-            bufsize = si.totalram/2;
-        }
-#else
-        bufsize = 16*1024*1024;
+        bufsize = (si.freeram/2)*si.mem_unit;
+        if (bufsize < 16*1024*1024)
 #endif
+        bufsize = 16*1024*1024;
     }
 
     cnt = bufsize/(priv->height*priv->bytesperline);
diff --git a/stream/tvi_v4l2.c b/stream/tvi_v4l2.c
index 234a5ac019..a3be9e799a 100644
--- a/stream/tvi_v4l2.c
+++ b/stream/tvi_v4l2.c
@@ -1376,7 +1376,8 @@ static int init(priv_t *priv)
 
 static int get_capture_buffer_size(priv_t *priv)
 {
-    int bufsize, cnt;
+    uint64_t bufsize;
+    int cnt;
 
     if (priv->tv_param->buffer_size >= 0) {
         bufsize = priv->tv_param->buffer_size*1024*1024;
@@ -1385,14 +1386,10 @@ static int get_capture_buffer_size(priv_t *priv)
         struct sysinfo si;
 
         sysinfo(&si);
-        if (si.totalram<2*1024*1024) {
-            bufsize = 1024*1024;
-        } else {
-            bufsize = si.totalram/2;
-        }
-#else
-        bufsize = 16*1024*1024;
+        bufsize = (si.freeram/2)*si.mem_unit;
+        if ( bufsize < 16*1024*1024)
 #endif
+        bufsize = 16*1024*1024;
     }
 
     cnt = bufsize/priv->format.fmt.pix.sizeimage;