Enable a shadow buffer and disable GPU acceleration.

An attempt to workaround the incoherency in gen2 chipsets, we avoid
using dynamic reallocation as much as possible.

The first step is to disable allocation of pixmaps using GEM and simply
create them in system memory without a backing buffer object. This
forces all rendering to use S/W fallbacks.

The second step is to allocate a shadow front buffer and assign that to
the Screen pixmap. This ensure that the front buffer remains in the GTT
and pinned for scanout. The shadow buffer will be rendered to in the
normal fashion via the Screen pixmap, and be marked dirty. In the block
handler, the dirty shadow buffer is then blitted (using the GPU) over
the front buffer. This should completely avoid having to move pages
around in the GTT and avoid incurring the wrath of those early chipsets.
Secondly, performance should be reasonable as we avoid the ping-pong
caused by the small aperture and weak GPU forcing software fallbacks.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 28 insertions, 17 deletions

diff --git a/src/intel_display.c b/src/intel_display.c
index ed3fdd07..e22c4153 100644
--- a/src/intel_display.c
+++ b/src/intel_display.c
@@ -488,12 +488,14 @@ intel_crtc_shadow_allocate(xf86CrtcPtr crtc, int width, int height)
 	struct intel_crtc *intel_crtc = crtc->driver_private;
 	struct intel_mode *mode = intel_crtc->mode;
 	unsigned long rotate_pitch;
+	uint32_t tiling;
 	int ret;
 
 	intel_crtc->rotate_bo = intel_allocate_framebuffer(scrn,
 							     width, height,
 							     mode->cpp,
-							     &rotate_pitch);
+							     &rotate_pitch,
+							     &tiling);
 
 	if (!intel_crtc->rotate_bo) {
 		xf86DrvMsg(crtc->scrn->scrnIndex, X_ERROR,
@@ -580,7 +582,7 @@ intel_crtc_shadow_destroy(xf86CrtcPtr crtc, PixmapPtr rotate_pixmap, void *data)
 		intel_crtc->rotate_bo = NULL;
 	}
 
-	intel->shadow_present = FALSE;
+	intel->shadow_present = intel->use_shadow;
 }
 
 static void
@@ -1310,11 +1312,10 @@ intel_xf86crtc_resize(ScrnInfoPtr scrn, int width, int height)
 	intel_screen_private *intel = intel_get_screen_private(scrn);
 	drm_intel_bo *old_front = NULL;
 	Bool	    ret;
-	ScreenPtr   screen = screenInfo.screens[scrn->scrnIndex];
-	PixmapPtr   pixmap;
 	uint32_t    old_fb_id;
 	int	    i, old_width, old_height, old_pitch;
 	unsigned long pitch;
+	uint32_t tiling;
 
 	if (scrn->virtualX == width && scrn->virtualY == height)
 		return TRUE;
@@ -1328,7 +1329,8 @@ intel_xf86crtc_resize(ScrnInfoPtr scrn, int width, int height)
 	intel->front_buffer = intel_allocate_framebuffer(scrn,
 							 width, height,
 							 intel->cpp,
-							 &pitch);
+							 &pitch,
+							 &tiling);
 	if (!intel->front_buffer)
 		goto fail;
 
@@ -1339,14 +1341,11 @@ intel_xf86crtc_resize(ScrnInfoPtr scrn, int width, int height)
 	if (ret)
 		goto fail;
 
+	intel->front_pitch = pitch;
+	intel->front_tiling = tiling;
+
 	scrn->virtualX = width;
 	scrn->virtualY = height;
-	scrn->displayWidth = pitch / intel->cpp;
-
-	pixmap = screen->GetScreenPixmap(screen);
-	screen->ModifyPixmapHeader(pixmap, width, height, -1, -1, pitch, NULL);
-	intel_set_pixmap_bo(pixmap, intel->front_buffer);
-	intel_get_pixmap_private(pixmap)->busy = 1;
 
 	for (i = 0; i < xf86_config->num_crtc; i++) {
 		xf86CrtcPtr crtc = xf86_config->crtc[i];
@@ -1358,6 +1357,8 @@ intel_xf86crtc_resize(ScrnInfoPtr scrn, int width, int height)
 			goto fail;
 	}
 
+	intel_uxa_create_screen_resources(scrn->pScreen);
+
 	if (old_fb_id)
 		drmModeRmFB(mode->fd, old_fb_id);
 	if (old_front)
@@ -1380,10 +1381,11 @@ fail:
 }
 
 Bool
-intel_do_pageflip(ScreenPtr screen, dri_bo *new_front, void *data)
+intel_do_pageflip(intel_screen_private *intel,
+		  dri_bo *new_front,
+		  void *data)
 {
-	ScrnInfoPtr scrn = xf86Screens[screen->myNum];
-	intel_screen_private *intel = intel_get_screen_private(scrn);
+	ScrnInfoPtr scrn = intel->scrn;
 	xf86CrtcConfigPtr config = XF86_CRTC_CONFIG_PTR(scrn);
 	struct intel_crtc *crtc = config->crtc[0]->driver_private;
 	struct intel_mode *mode = crtc->mode;
@@ -1454,22 +1456,31 @@ intel_page_flip_handler(int fd, unsigned int frame, unsigned int tv_sec,
 {
 	struct intel_mode *mode = event_data;
 
+
 	mode->flip_count--;
 	if (mode->flip_count > 0)
 		return;
 
 	drmModeRmFB(mode->fd, mode->old_fb_id);
 
+	if (mode->event_data == NULL)
+		return;
+
 	I830DRI2FlipEventHandler(frame, tv_sec, tv_usec, mode->event_data);
 }
 
 static void
 drm_wakeup_handler(pointer data, int err, pointer p)
 {
-	struct intel_mode *mode = data;
-	fd_set *read_mask = p;
+	struct intel_mode *mode;
+	fd_set *read_mask;
+
+	if (data == NULL || err < 0)
+		return;
 
-	if (err >= 0 && FD_ISSET(mode->fd, read_mask))
+	mode = data;
+	read_mask = p;
+	if (FD_ISSET(mode->fd, read_mask))
 		drmHandleEvent(mode->fd, &mode->event_context);
 }