Nouveau - Mar 2017 - [DDX PATCH] Consider CRTCs disabled when DPMS is off

It turns out there's a difference in X between a CRTC being
"disabled"
and simply having it's DPMS turned off. This is problematic though,
because if DPMS is turned off you can't really use the CRTC as a normal
CRTC anyway since page flipping and vblanks will be non-functional. As a
result, we've been considering DPMS-on CRTCs as enabled and attempt to
perform pageflips, vblank waits, etc. on them which inevitably fails. and
usually breaks the display the first time any of the CRTCs have their
DPMS turned on.

This was a problem that didn't really show itself until kernel 4.10 when
atomic modesetting was added which caused nouveau to stop trying to
fulfill pageflips and vblank waits on disabled CRTCs. I'm not sure how
pageflipping disabled CRTCs ever worked in the first place, but since
not doing so is the proper behavior anyway I haven't investigated any
further.

So, copy the ms_crtc_on() function from the modesetting driver and add
it here as drmmode_crtc_on(), then use that in all of the places where
we should be checking for both DPMS off and disabled CRTCs.

This fixes issues with the X ceasing to function (usually) after the
first time a CRTC has it's DPMS turned on. Reproduction recipe:

- Load up gnome-shell on a machine
- Wait for the display to timeout from inactivity and turn itself off
- Shake the cursor or press something on the keyboard. Chances are the
  monitor will come back on, but the display remains black until the
  next time the X server is restarted.

Signed-off-by: Lyude <lyude at redhat.com>
---
 src/drmmode_display.c | 14 ++++++++++++--
 src/nouveau_dri2.c    | 14 +++++++++-----
 src/nouveau_present.c |  6 +++---
 src/nouveau_xv.c      |  2 +-
 src/nv_proto.h        |  1 +
 5 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/src/drmmode_display.c b/src/drmmode_display.c
index b6c9bb9..dd9fa27 100644
--- a/src/drmmode_display.c
+++ b/src/drmmode_display.c
@@ -65,6 +65,7 @@ typedef struct {
     uint32_t rotate_fb_id;
     Bool cursor_visible;
     int scanout_pixmap_x;
+    int dpms_mode;
 } drmmode_crtc_private_rec, *drmmode_crtc_private_ptr;
 
 typedef struct {
@@ -114,6 +115,14 @@ drmmode_crtc(xf86CrtcPtr crtc)
 	return drmmode_crtc->mode_crtc->crtc_id;
 }
 
+Bool
+drmmode_crtc_on(xf86CrtcPtr crtc)
+{
+    drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
+
+    return crtc->enabled && drmmode_crtc->dpms_mode ==
DPMSModeOn;
+}
+
 int
 drmmode_head(xf86CrtcPtr crtc)
 {
@@ -313,9 +322,10 @@ drmmode_ConvertToKMode(ScrnInfoPtr scrn, drmModeModeInfo
*kmode,
 }
 
 static void
-drmmode_crtc_dpms(xf86CrtcPtr drmmode_crtc, int mode)
+drmmode_crtc_dpms(xf86CrtcPtr crtc, int mode)
 {
-
+	drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
+	drmmode_crtc->dpms_mode = mode;
 }
 
 void
diff --git a/src/nouveau_dri2.c b/src/nouveau_dri2.c
index 81ee9be..cbb7b2a 100644
--- a/src/nouveau_dri2.c
+++ b/src/nouveau_dri2.c
@@ -279,23 +279,27 @@ can_exchange(DrawablePtr draw, PixmapPtr dst_pix,
PixmapPtr src_pix)
 	ScrnInfoPtr scrn = xf86ScreenToScrn(draw->pScreen);
 	xf86CrtcConfigPtr xf86_config = XF86_CRTC_CONFIG_PTR(scrn);
 	NVPtr pNv = NVPTR(scrn);
-	int i;
+	int i, active_crtc_count = 0;
 
 	if (!xf86_config->num_crtc)
 		return FALSE;
 
 	for (i = 0; i < xf86_config->num_crtc; i++) {
 		xf86CrtcPtr crtc = xf86_config->crtc[i];
-		if (crtc->enabled && crtc->rotatedData)
-			return FALSE;
+		if (drmmode_crtc_on(crtc)) {
+			if (crtc->rotatedData)
+				return FALSE;
 
+			active_crtc_count++;
+		}
 	}
 
 	return ((DRI2CanFlip(draw) && pNv->has_pageflip)) &&
 		dst_pix->drawable.width == src_pix->drawable.width &&
 		dst_pix->drawable.height == src_pix->drawable.height &&
 		dst_pix->drawable.bitsPerPixel == src_pix->drawable.bitsPerPixel
&&
-		dst_pix->devKind == src_pix->devKind;
+		dst_pix->devKind == src_pix->devKind &&
+		active_crtc_count;
 }
 
 static Bool
@@ -475,7 +479,7 @@ dri2_page_flip(DrawablePtr draw, PixmapPtr back, void *priv,
 		int head = drmmode_crtc(config->crtc[i]);
 		void *token;
 
-		if (!config->crtc[i]->enabled)
+		if (!drmmode_crtc_on(config->crtc[i]))
 			continue;
 
 		flipdata->flip_count++;
diff --git a/src/nouveau_present.c b/src/nouveau_present.c
index 482ac6e..ebd5fcf 100644
--- a/src/nouveau_present.c
+++ b/src/nouveau_present.c
@@ -152,7 +152,7 @@ nouveau_present_flip_check(RRCrtcPtr rrcrtc, WindowPtr
window,
 	ScrnInfoPtr scrn = xf86ScreenToScrn(window->drawable.pScreen);
 	xf86CrtcPtr crtc = rrcrtc->devPrivate;
 
-	if (!scrn->vtSema || !crtc->enabled)
+	if (!scrn->vtSema || !drmmode_crtc_on(crtc))
 		return FALSE;
 
 	return TRUE;
@@ -199,7 +199,7 @@ nouveau_present_flip_exec(ScrnInfoPtr scrn, uint64_t
event_id, int sync,
 			flip->msc = target_msc;
 
 			for (i = 0; i < config->num_crtc; i++) {
-				if (config->crtc[i]->enabled)
+				if (drmmode_crtc_on(config->crtc[i]))
 					last = i;
 			}
 
@@ -208,7 +208,7 @@ nouveau_present_flip_exec(ScrnInfoPtr scrn, uint64_t
event_id, int sync,
 				int crtc = drmmode_crtc(config->crtc[i]);
 				void *user = NULL;
 
-				if (!config->crtc[i]->enabled)
+				if (!drmmode_crtc_on(config->crtc[i]))
 					continue;
 
 				if (token && ((crtc == sync) || (i == last))) {
diff --git a/src/nouveau_xv.c b/src/nouveau_xv.c
index 716b18d..4b939f7 100644
--- a/src/nouveau_xv.c
+++ b/src/nouveau_xv.c
@@ -299,7 +299,7 @@ nv_window_belongs_to_crtc(ScrnInfoPtr pScrn, int x, int y,
int w, int h)
 	for (i = 0; i < xf86_config->num_crtc; i++) {
 		xf86CrtcPtr crtc = xf86_config->crtc[i];
 
-		if (!crtc->enabled)
+		if (!drmmode_crtc_on(crtc))
 			continue;
 
 		if ((x < (crtc->x + crtc->mode.HDisplay)) &&
diff --git a/src/nv_proto.h b/src/nv_proto.h
index 122ede5..4a57406 100644
--- a/src/nv_proto.h
+++ b/src/nv_proto.h
@@ -13,6 +13,7 @@ void drmmode_screen_init(ScreenPtr pScreen);
 void drmmode_screen_fini(ScreenPtr pScreen);
 
 int  drmmode_crtc(xf86CrtcPtr crtc);
+Bool drmmode_crtc_on(xf86CrtcPtr crtc);
 int  drmmode_head(xf86CrtcPtr crtc);
 void drmmode_swap(ScrnInfoPtr, uint32_t, uint32_t *);
 
-- 
2.9.3