vmwgfx: Add an option for direct presents

With this option set to true, accelerated copies to a scanout pixmap will
be performed as hardware presents instead of copies to an intermediate
3D surface backing the scanout pixmap, followed by a present.

Depending on the application this might be a performance boost, but since
it might trigger device software readbacks in other situations, for example
dri2 copy front->fake_front, it might be a performance hog in other situations,
so disable it by default. (Before this commit it was enabled by default).

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>

4 files changed, 22 insertions, 5 deletions

diff --git a/vmwgfx/vmwgfx_driver.c b/vmwgfx/vmwgfx_driver.c
index 132c617..4ac829f 100644
--- a/vmwgfx/vmwgfx_driver.c
+++ b/vmwgfx/vmwgfx_driver.c
@@ -105,13 +105,15 @@ typedef enum
 {
     OPTION_SW_CURSOR,
     OPTION_RENDER_ACCEL,
-    OPTION_DRI
+    OPTION_DRI,
+    OPTION_DIRECT_PRESENTS,
 } drv_option_enums;
 
 static const OptionInfoRec drv_options[] = {
     {OPTION_SW_CURSOR, "SWcursor", OPTV_BOOLEAN, {0}, FALSE},
     {OPTION_RENDER_ACCEL, "RenderAccel", OPTV_BOOLEAN, {0}, FALSE},
     {OPTION_DRI, "DRI", OPTV_BOOLEAN, {0}, FALSE},
+    {OPTION_DIRECT_PRESENTS, "DirectPresents", OPTV_BOOLEAN, {0}, FALSE},
     {-1, NULL, OPTV_NONE, {0}, FALSE}
 };
 
@@ -410,6 +412,11 @@ drv_pre_init(ScrnInfoPtr pScrn, int flags)
 				     &ms->enable_dri) ?
 	X_CONFIG : X_PROBED;
 
+    ms->direct_presents = FALSE;
+    ms->from_dp = xf86GetOptValBool(ms->Options, OPTION_DIRECT_PRESENTS,
+				    &ms->direct_presents) ?
+	X_CONFIG : X_DEFAULT;
+
     /* Allocate an xf86CrtcConfig */
     xf86CrtcConfigInit(pScrn, &crtc_config_funcs);
     xf86_config = XF86_CRTC_CONFIG_PTR(pScrn);
@@ -908,7 +915,8 @@ drv_screen_init(int scrnIndex, ScreenPtr pScreen, int argc, char **argv)
 	}
     }
 
-    if (!vmwgfx_saa_init(pScreen, ms->fd, ms->xat, &xorg_flush)) {
+    if (!vmwgfx_saa_init(pScreen, ms->fd, ms->xat, &xorg_flush,
+			 ms->direct_presents)) {
 	FatalError("Failed to initialize SAA.\n");
     }
 
@@ -933,6 +941,10 @@ drv_screen_init(int scrnIndex, ScreenPtr pScreen, int argc, char **argv)
 	       (ms->xat != NULL) ? "enabled" : "disabled");
     xf86DrvMsg(pScrn->scrnIndex, ms->from_dri, "Direct rendering (3D) is %s.\n",
 	       (ms->dri2_available) ? "enabled" : "disabled");
+    if (ms->xat != NULL) {
+	xf86DrvMsg(pScrn->scrnIndex, ms->from_dp, "Direct presents are %s.\n",
+		   (ms->direct_presents) ? "enabled" : "disabled");
+    }
 
     miInitializeBackingStore(pScreen);
     xf86SetBackingStore(pScreen);
diff --git a/vmwgfx/vmwgfx_driver.h b/vmwgfx/vmwgfx_driver.h
index fd750ca..a88fa82 100644
--- a/vmwgfx/vmwgfx_driver.h
+++ b/vmwgfx/vmwgfx_driver.h
@@ -92,8 +92,11 @@ typedef struct _modesettingRec
     CursorPtr cursor;
     Bool enable_dri;
     Bool from_dri;
+    Bool direct_presents;
+    Bool from_dp;
     Bool isMaster;
 
+
     /* Broken-out options. */
     OptionInfoPtr Options;
 
diff --git a/vmwgfx/vmwgfx_saa.c b/vmwgfx/vmwgfx_saa.c
index 4638ef0..66c6cfc 100644
--- a/vmwgfx/vmwgfx_saa.c
+++ b/vmwgfx/vmwgfx_saa.c
@@ -1270,7 +1270,8 @@ static const struct saa_driver vmwgfx_saa_driver = {
 
 Bool
 vmwgfx_saa_init(ScreenPtr pScreen, int drm_fd, struct xa_tracker *xat,
-		void (*present_flush)(ScreenPtr pScreen))
+		void (*present_flush)(ScreenPtr pScreen),
+		Bool direct_presents)
 {
     struct vmwgfx_saa *vsaa;
 
@@ -1285,7 +1286,7 @@ vmwgfx_saa_init(ScreenPtr pScreen, int drm_fd, struct xa_tracker *xat,
     vsaa->drm_fd = drm_fd;
     vsaa->present_flush = present_flush;
     vsaa->can_optimize_dma = FALSE;
-    vsaa->use_present_opt = TRUE;
+    vsaa->use_present_opt = direct_presents;
     vsaa->only_hw_presents = FALSE;
     WSBMINITLISTHEAD(&vsaa->sync_x_list);
 
diff --git a/vmwgfx/vmwgfx_saa.h b/vmwgfx/vmwgfx_saa.h
index 30eeacc..1fd06b6 100644
--- a/vmwgfx/vmwgfx_saa.h
+++ b/vmwgfx/vmwgfx_saa.h
@@ -80,7 +80,8 @@ vmwgfx_saa_pixmap(PixmapPtr pix)
 
 extern Bool
 vmwgfx_saa_init(ScreenPtr pScreen, int drm_fd, struct xa_tracker *xat,
-		void (*present_flush)(ScreenPtr pScreen));
+		void (*present_flush)(ScreenPtr pScreen),
+		Bool direct_presents);
 
 extern uint32_t
 vmwgfx_scanout_ref(struct vmwgfx_screen_entry *box);