.\" This manpage has been automatically generated by docbook2man 
.\" from a DocBook document.  This tool can be found at:
.\" <http://shell.ipoline.com/~elmert/comp/docbook2X/> 
.\" Please send any bug reports, improvements, comments, patches, 
.\" etc. to Steve Cheng <steve@ggi-project.org>.
.TH "FB_GET_VBLANK" "9" "09 October 2005" "" ""

.SH NAME
fb_get_vblank \- get vertical blank time
.SH SYNOPSIS
"SYNOPSIS"
.sp
\fB
.sp
u32 fb_get_vblank  (u32 \fIhfreq\fB);
\fR
.SH "ARGUMENTS"
.TP
\fB\fIhfreq\fB\fR
horizontal freq
.SH "DESCRIPTION"
.PP
vblank = right_margin + vsync_len + left_margin 
.SH "GIVEN"
.PP
right_margin = 1 (V_FRONTPORCH)
vsync_len    = 3
flyback      = 550
.PP
flyback * hfreq
left_margin  = --------------- - vsync_len
1000000