[MPlayer-dev-eng] [PATCH] Improved DGA vertical retrace sync
Fredrik Noring
noring at nocrew.org
Sun Sep 22 22:32:57 CEST 2002
Attached patch improves the vertical retrace synchronisation (vsync)
of the mplayer DGA driver.
It implements a more general buffer scheme than double buffers that
allows for deeper buffer queues. This makes it less likely that mplayer
tries to draw in buffers that are currently displayed, or buffers that
soon are about to be displayed.
The buffers (up to 9 on a simple Riva 128 card) are located in graphics
memory, and this can later be exploited by Mplayer since it can make
Mplayer much less sensitive to scheduling problems.
Performance note on DGA that applies to both the current code and
code with the attached patch:
To take full advantage of the mplayer DGA driver, busy-waits in
the XDGASetViewport function in the XFree86 DGA drivers needs to be
eliminated.
This is a problem in for example the Nvidia "nv" driver. I have a
work-around patch which improves the situation for the Nvidia DGA
driver in XFree86. It uses /dev/rtc; a long-term solution would
likely need some other kind of kernel support however. (In some
simple tests I've done, XFree86 4.0.2 normally wastes around
20-40 % cpu on busy-waiting.)
Comments?
Fredrik
Index: vo_dga.c
===================================================================
RCS file: /cvsroot/mplayer/main/libvo/vo_dga.c,v
retrieving revision 1.46
diff -u -r1.46 vo_dga.c
--- vo_dga.c 28 Aug 2002 21:32:31 -0000 1.46
+++ vo_dga.c 22 Sep 2002 20:30:06 -0000
@@ -374,14 +374,26 @@
static int vo_dga_XServer_mode = 0;// index in mode list for resolution
// XServer is running
-static int vo_dga_dbf_mem_offset; // offset in bytes for alternative
- // framebuffer (0 if dbf is not
- // possible)
-static int vo_dga_dbf_y_offset; // y offset (in scanlines)
-static int
- vo_dga_dbf_current; // current buffer (0 or 1)
+#define MAX_NR_VIDEO_BUFFERS 5
+
+#define VIDEO_BUFFER_DRAW \
+ (vo_dga_video_buffer[vo_dga_current_video_buffer % \
+ vo_dga_nr_video_buffers])
+
+#define VIDEO_BUFFER_DISPLAY \
+ (vo_dga_video_buffer[(vo_dga_current_video_buffer + \
+ vo_dga_nr_video_buffers - 1) % \
+ vo_dga_nr_video_buffers])
+
+static int vo_dga_nr_video_buffers; // Total number of frame buffers.
+static int vo_dga_current_video_buffer; // Buffer available for rendering.
+
+static struct video_buffer
+{
+ int y;
+ uint8_t *data;
+} vo_dga_video_buffer[MAX_NR_VIDEO_BUFFERS];
-static unsigned char *vo_dga_base;
static Display *vo_dga_dpy;
/* saved src and dst dimensions for SwScaler */
@@ -421,7 +433,7 @@
offset = vo_dga_width * y0 +x0;
buffer_stride = vo_dga_width;
- d = (&((char *)vo_dga_base)[vo_dga_vp_offset + vo_dga_dbf_current * vo_dga_dbf_mem_offset]);
+ d = VIDEO_BUFFER_DRAW.data;
switch( HW_MODE.vdm_mplayer_depth ){
@@ -468,7 +480,7 @@
char *s, *d;
s = *src;
- d = (&((char *)vo_dga_base)[vo_dga_vp_offset + vo_dga_dbf_current * vo_dga_dbf_mem_offset]);
+ d = VIDEO_BUFFER_DRAW.data;
switch(SRC_MODE.vdm_conversion_func){
case VDM_CONV_NATIVE:
@@ -479,18 +491,18 @@
numlines,
vo_dga_bytes_per_line+vo_dga_vp_skip,
vo_dga_bytes_per_line);
-
+
// DBG-COde
#if 0
- d = (&((char *)vo_dga_base)[vo_dga_vp_offset + vo_dga_dbf_current * vo_dga_dbf_mem_offset]);
+ d = VIDEO_BUFFER_DRAW.data;
fillblock(d, 0, 10, 0x800000ff);
fillblock(d, 10, 10, 0x8000ff00);
fillblock(d, 20, 10, 0x80ff0000);
fillblock(d, 30, 10, 0xff0000ff);
fillblock(d, 40, 10, 0x800000ff);
fillblock(d, 50, 10, 0x0f0000ff);
-#endif
+#endif
break;
case VDM_CONV_15TO16:
{
@@ -539,20 +551,28 @@
static void draw_osd(void)
{ vo_draw_text(vo_dga_src_width,vo_dga_src_height,draw_alpha); }
-static void flip_page( void ){
-
- if(vo_dga_dbf_mem_offset != 0){
+static void switch_video_buffers(void)
+{
+ vo_dga_current_video_buffer =
+ (vo_dga_current_video_buffer + 1) % vo_dga_nr_video_buffers;
+}
+static void flip_page( void )
+{
+ if(1 < vo_dga_nr_video_buffers)
+ {
#ifdef HAVE_DGA2
- XDGASetViewport (vo_dga_dpy, XDefaultScreen(vo_dga_dpy),
- 0, vo_dga_dbf_current * vo_dga_dbf_y_offset,
- XDGAFlipRetrace);
+ XDGASetViewport(vo_dga_dpy, XDefaultScreen(vo_dga_dpy),
+ 0,
+ VIDEO_BUFFER_DISPLAY.y,
+ XDGAFlipRetrace);
#else
- XF86DGASetViewPort (vo_dga_dpy, XDefaultScreen(vo_dga_dpy),
- 0, vo_dga_dbf_current * vo_dga_dbf_y_offset);
+ XF86DGASetViewPort(vo_dga_dpy, XDefaultScreen(vo_dga_dpy),
+ 0,
+ VIDEO_BUFFER_DISPLAY.y);
#endif
- vo_dga_dbf_current = 1 - vo_dga_dbf_current;
- }
+ switch_video_buffers();
+ }
}
//---------------------------------------------------------
@@ -561,13 +581,18 @@
int w,int h,int x,int y )
{
if (scale_srcW) {
- uint8_t *dst[3] = {vo_dga_base + vo_dga_dbf_current * vo_dga_dbf_mem_offset + vo_dga_vp_offset, NULL, NULL};
+ uint8_t *dst[3] =
+ {
+ VIDEO_BUFFER_DRAW.data + vo_dga_vp_offset,
+ 0,
+ 0
+ };
SwScale_YV12slice(src,stride,y,h,
dst,
/*scale_dstW*/ vo_dga_width * HW_MODE.vdm_bytespp, HW_MODE.vdm_bitspp,
scale_srcW, scale_srcH, scale_dstW, scale_dstH);
} else {
- yuv2rgb( vo_dga_base + vo_dga_dbf_current * vo_dga_dbf_mem_offset + vo_dga_vp_offset +
+ yuv2rgb(VIDEO_BUFFER_DRAW.data + vo_dga_vp_offset +
(vo_dga_width * y +x) * HW_MODE.vdm_bytespp,
src[0], src[1], src[2],
w,h, vo_dga_width * HW_MODE.vdm_bytespp,
@@ -796,6 +821,31 @@
//---------------------------------------------------------
+static void init_video_buffers(XDGAMode *modeline, uint8_t *buffer_base)
+{
+ int bytes_per_buffer =
+ modeline->viewportHeight * modeline->bytesPerScanline;
+ int i;
+
+ vo_dga_nr_video_buffers =
+ modeline->pixmapHeight / modeline->viewportHeight;
+
+ vo_dga_current_video_buffer = 0;
+
+ if(MAX_NR_VIDEO_BUFFERS < vo_dga_nr_video_buffers)
+ vo_dga_nr_video_buffers = MAX_NR_VIDEO_BUFFERS;
+
+ for(i = 0; i < vo_dga_nr_video_buffers; i++)
+ {
+ vo_dga_video_buffer[i].y = i * modeline->viewportHeight;
+ vo_dga_video_buffer[i].data =
+ buffer_base + i * bytes_per_buffer;
+
+ // Clear video buffer.
+ memset(vo_dga_video_buffer[i].data, 0, bytes_per_buffer);
+ }
+}
+
static uint32_t config( uint32_t width, uint32_t height,
uint32_t d_width,uint32_t d_height,
uint32_t flags,char *title,uint32_t format)
@@ -808,8 +858,9 @@
// needed to change DGA video mode
int modecount, mX=VO_DGA_INVALID_RES, mY=VO_DGA_INVALID_RES , mVBI=100000, mMaxY=0, i,j=0;
int dga_modenum;
- XDGAMode *modelines=NULL;
+ XDGAMode *modelines=NULL, *modeline;
XDGADevice *dgadevice;
+ unsigned char *vo_dga_base;
int max_vpy_pos;
#else
#ifdef HAVE_XF86VM
@@ -947,6 +998,7 @@
vo_dga_width = modelines[j].bytesPerScanline / HW_MODE.vdm_bytespp ;
dga_modenum = modelines[j].num;
max_vpy_pos = modelines[j].maxViewportY;
+ modeline = modelines + j;
XFree(modelines);
modelines = NULL;
@@ -1120,50 +1172,9 @@
XGrabPointer (vo_dga_dpy, DefaultRootWindow(vo_dga_dpy), True,
ButtonPressMask,GrabModeAsync, GrabModeAsync,
None, None, CurrentTime);
-// TODO: chekc if mem of graphics adaptor is large enough for dbf
- // set up variables for double buffering ...
- // note: set vo_dga_dbf_mem_offset to NULL to disable doublebuffering
+ init_video_buffers(modeline, vo_dga_base);
- vo_dga_dbf_y_offset = y_off + vo_dga_src_height;
- vo_dga_dbf_mem_offset = vo_dga_width * HW_MODE.vdm_bytespp * vo_dga_dbf_y_offset;
- vo_dga_dbf_current = 0;
-
-
- if(!vo_doublebuffering) vo_dga_dbf_mem_offset = 0;
-
- // if(format ==IMGFMT_YV12 )
- //vo_dga_dbf_mem_offset = 0;
- // disable doublebuffering for YV12
-
-#ifdef HAVE_DGA2
- if(vo_dga_vp_height>max_vpy_pos){
- vo_dga_dbf_mem_offset = 0;
- vd_printf(VD_INFO, "vo_dga: Not enough memory for double buffering!\n");
- }
-#endif
-
- // now clear screen
- {
- int size = vo_dga_width *
- (vo_dga_vp_height + (vo_dga_dbf_mem_offset != 0 ?
- (vo_dga_src_height+y_off) : 0)) *
- HW_MODE.vdm_bytespp;
-#ifndef HAVE_DGA2
- vd_printf(VD_DBG, "vo_dga: wanted size=%d, fb-size=%d\n", size, ram);
- if(size>ram*1024){
- vo_dga_dbf_mem_offset = 0;
- vd_printf(VD_INFO, "vo_dga: Not enough memory for double buffering!\n");
- size -= (vo_dga_src_height+y_off) * vo_dga_width * HW_MODE.vdm_bytespp;
- }
-#endif
-
- vd_printf(VD_INFO, "vo_dga: Clearing framebuffer (%d bytes). If mplayer exits", size);
- vd_printf(VD_INFO, " here, you haven't enough memory on your card.\n");
- fflush(stdout);
- memset(vo_dga_base, 0, size);
- }
- vd_printf(VD_INFO, "vo_dga: Doublebuffering is %s.\n", vo_dga_dbf_mem_offset ? "enabled" : "disabled");
vo_dga_is_running = 1;
return 0;
}
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