Wordpress pagination on homepage not working - wordpress

Question

pls i need your help,
the pagination on my homepage does not work...whenevr i click on the 2 button to go to second page, i get a 404 error page.
here is the pagination code;
if ( !function_exists( 'pagination' ) ) {
function pagination($pages = '', $range = 4)
{
$showitems = ($range * 2)+1;
global $paged;
if(empty($paged)) $paged = 1;
if($pages == '')
{
global $wp_query;
$pages = $wp_query->max_num_pages;
if(!$pages)
{
$pages = 1;
}
}
if(1 != $pages)
{
echo "<div class=\"pagination\"><span>Page ".$paged." of ".$pages."</span>";
if($paged > 2 && $paged > $range+1 && $showitems < $pages) echo "<a href='".get_pagenum_link(1)."'>« First</a>";
if($paged > 1 && $showitems < $pages) echo "<a href='".get_pagenum_link($paged - 1)."'>‹ Previous</a>";
for ($i=1; $i <= $pages; $i++)
{
if (1 != $pages &&( !($i >= $paged+$range+1 || $i <= $paged-$range-1) || $pages <= $showitems ))
{
echo ($paged == $i)? "<span class=\"current\">".$i."</span>":"".$i."";
}
}
if ($paged < $pages && $showitems < $pages) echo "Next ›";
if ($paged < $pages-1 && $paged+$range-1 < $pages && $showitems < $pages) echo "<a href='".get_pagenum_link($pages)."'>Last »</a>";
echo "</div>\n";
}
}
}

Answer 1

Place this code in functions.php and try., Replace the post type and posts_per_page as you need..
function alter_query_vars($query)
{
switch($query->query_vars['post_type'])
{
case 'post':
//if($query->is_category()) Use this if you want to pagination on category page
$query->query_vars['posts_per_page'] = 6;
break;
default:
break;
}
return $query;
}
add_action('pre_get_posts', 'alter_query_vars');