sna: Haswell reintroduces MI_LOAD_SCAN_LINES

Better late than never? Interestingly only available from the BLT ring,
which makes accurate waiting for XVideo (which must use the render ring)
impossible in the current form - we need to render to a temporary then
do a vsynced blit in this case.

References: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1156679
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 41 insertions, 5 deletions

diff --git a/src/sna/sna_display.c b/src/sna/sna_display.c
index abb340a7..9068df99 100644
--- a/src/sna/sna_display.c
+++ b/src/sna/sna_display.c
@@ -2806,12 +2806,46 @@ sna_covering_crtc(ScrnInfoPtr scrn,
 	return best_crtc;
 }
 
+static bool sna_emit_wait_for_scanline_hsw(struct sna *sna,
+					   xf86CrtcPtr crtc,
+					   int pipe, int y1, int y2,
+					   bool full_height)
+{
+	uint32_t event;
+	uint32_t *b;
+
+	if (sna->kgem.mode != KGEM_BLT)
+		return false;
+
+	b = kgem_get_batch(&sna->kgem);
+	sna->kgem.nbatch += 5;
+
+	/* The documentation says that the LOAD_SCAN_LINES command
+	 * always comes in pairs. Don't ask me why. */
+	switch (pipe) {
+	case 0: event = 0; break;
+	case 1: event = 1 << 19; break;
+	case 2: event = 4 << 19; break;
+	}
+	b[2] = b[0] = MI_LOAD_SCAN_LINES_INCL | event;
+	b[3] = b[1] = (y1 << 16) | (y2-1);
+
+	switch (pipe) {
+	case 0: event = 0; break;
+	case 1: event = 1 << 8; break;
+	case 2: event = 1 << 14; break;
+	}
+	b[4] = MI_WAIT_FOR_EVENT | event;
+
+	return true;
+}
+
 #define MI_LOAD_REGISTER_IMM			(0x22<<23)
 
-static bool sna_emit_wait_for_scanline_gen7(struct sna *sna,
-					    xf86CrtcPtr crtc,
-					    int pipe, int y1, int y2,
-					    bool full_height)
+static bool sna_emit_wait_for_scanline_ivb(struct sna *sna,
+					   xf86CrtcPtr crtc,
+					   int pipe, int y1, int y2,
+					   bool full_height)
 {
 	uint32_t *b;
 	uint32_t event;
@@ -3022,10 +3056,12 @@ sna_wait_for_scanline(struct sna *sna,
 
 	if (sna->kgem.gen >= 0100)
 		ret = false;
+	else if (sna->kgem.gen >= 075)
+		ret = sna_emit_wait_for_scanline_hsw(sna, crtc, pipe, y1, y2, full_height);
 	else if (sna->kgem.gen == 071)
 		ret =sna_emit_wait_for_scanline_gen6(sna, crtc, pipe, y1, y2, full_height);
 	else if (sna->kgem.gen >= 070)
-		ret = sna_emit_wait_for_scanline_gen7(sna, crtc, pipe, y1, y2, full_height);
+		ret = sna_emit_wait_for_scanline_ivb(sna, crtc, pipe, y1, y2, full_height);
 	else if (sna->kgem.gen >= 060)
 		ret =sna_emit_wait_for_scanline_gen6(sna, crtc, pipe, y1, y2, full_height);
 	else if (sna->kgem.gen >= 040)