[Nouveau] [PATCH] nv50/disp: Fix modeset on G94

[Roy Spliet]

Commit 1dce6264045cd23e9c07574ed0bb31c7dce9354f introduced a regression spotted
on several G94 (FDObz #85160). This device seems to expect the vblank period to
be set after setting scale instead of before.

This is a candidate bug-fix for 3.18

Signed-off-by: Roy Spliet <rspliet at eclipso.eu>
Tested-by: Zlatko Calusic <zcalusic at bitsync.net>
Tested-by: Michael Riesch <michael at riesch.at>
Tested-by: "poma" <pomidorabelisima at gmail.com>
---
 drivers/gpu/drm/nouveau/nv50_display.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nv50_display.c b/drivers/gpu/drm/nouveau/nv50_display.c
index ae873d1..5beb352 100644
--- a/drivers/gpu/drm/nouveau/nv50_display.c
+++ b/drivers/gpu/drm/nouveau/nv50_display.c
@@ -1104,14 +1104,14 @@ nv50_crtc_mode_set(struct drm_crtc *crtc, struct drm_display_mode *umode,
 			evo_mthd(push, 0x0804 + (nv_crtc->index * 0x400), 2);
 			evo_data(push, 0x00800000 | mode->clock);
 			evo_data(push, (ilace == 2) ? 2 : 0);
-			evo_mthd(push, 0x0810 + (nv_crtc->index * 0x400), 8);
+			evo_mthd(push, 0x0810 + (nv_crtc->index * 0x400), 6);
 			evo_data(push, 0x00000000);
 			evo_data(push, (vactive << 16) | hactive);
 			evo_data(push, ( vsynce << 16) | hsynce);
 			evo_data(push, (vblanke << 16) | hblanke);
 			evo_data(push, (vblanks << 16) | hblanks);
 			evo_data(push, (vblan2e << 16) | vblan2s);
-			evo_data(push, vblankus);
+			evo_mthd(push, 0x082c + (nv_crtc->index * 0x400), 1);
 			evo_data(push, 0x00000000);
 			evo_mthd(push, 0x0900 + (nv_crtc->index * 0x400), 2);
 			evo_data(push, 0x00000311);
@@ -1141,6 +1141,17 @@ nv50_crtc_mode_set(struct drm_crtc *crtc, struct drm_display_mode *umode,
 	nv_connector = nouveau_crtc_connector_get(nv_crtc);
 	nv50_crtc_set_dither(nv_crtc, false);
 	nv50_crtc_set_scale(nv_crtc, false);
+
+	/* G94 only accepts this after setting scale */
+	if (nv50_vers(mast) < GF110_DISP_CORE_CHANNEL_DMA) {
+		push = evo_wait(mast, 8);
+		if (push) {
+			evo_mthd(push, 0x0828 + (nv_crtc->index * 0x400), 1);
+			evo_data(push, vblankus);
+			evo_kick(push, mast);
+		}
+	}
+
 	nv50_crtc_set_color_vibrance(nv_crtc, false);
 	nv50_crtc_set_image(nv_crtc, crtc->primary->fb, x, y, false);
 	return 0;
-- 
2.1.0