drm/qxl: cover all crtcs in shadow bo.

The qxl device supports only a single active framebuffer ("primary
surface" in spice terminology).  In multihead configurations are handled
by defining rectangles within the primary surface for each head/crtc.

Userspace which uses the qxl ioctl interface (xorg qxl driver) is aware
of this limitation and will setup framebuffers and crtcs accordingly.

Userspace which uses dumb framebuffers (xorg modesetting driver,
wayland) is not aware of this limitation and tries to use two
framebuffers (one for each crtc) instead.

The qxl kms driver already has the dumb bo separated from the primary
surface, by using a (shared) shadow bo as primary surface.  This is
needed to support pageflips without having to re-create the primary
surface.  The qxl driver will blit from the dumb bo to the shadow bo
instead.

So we can extend the shadow logic:  Maintain a global shadow bo (aka
primary surface), make it big enough that dumb bo's for all crtcs fit in
side-by-side.  Adjust the pageflip blits to place the heads next to each
other in the shadow.

With this patch in place multihead qxl works with wayland.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20190118122020.27596-15-kraxel@redhat.com

1 files changed, 97 insertions, 26 deletions

diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
index 455b1b595a09..3f2e253f7244 100644
--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -323,6 +323,8 @@ static void qxl_crtc_update_monitors_config(struct drm_crtc *crtc,
 		head.y = crtc->y;
 		if (qdev->monitors_config->count < i + 1)
 			qdev->monitors_config->count = i + 1;
+		if (qdev->primary_bo == qdev->dumb_shadow_bo)
+			head.x += qdev->dumb_heads[i].x;
 	} else if (i > 0) {
 		head.width = 0;
 		head.height = 0;
@@ -426,7 +428,7 @@ static int qxl_framebuffer_surface_dirty(struct drm_framebuffer *fb,
 	}
 
 	qxl_draw_dirty_fb(qdev, fb, qobj, flags, color,
-			  clips, num_clips, inc);
+			  clips, num_clips, inc, 0);
 
 	drm_modeset_unlock_all(fb->dev);
 
@@ -535,6 +537,7 @@ static void qxl_primary_atomic_update(struct drm_plane *plane,
 	    .x2 = plane->state->fb->width,
 	    .y2 = plane->state->fb->height
 	};
+	uint32_t dumb_shadow_offset = 0;
 
 	if (old_state->fb) {
 		bo_old = gem_to_qxl_bo(old_state->fb->obj[0]);
@@ -551,7 +554,12 @@ static void qxl_primary_atomic_update(struct drm_plane *plane,
 		qxl_primary_apply_cursor(plane);
 	}
 
-	qxl_draw_dirty_fb(qdev, plane->state->fb, bo, 0, 0, &norect, 1, 1);
+	if (bo->is_dumb)
+		dumb_shadow_offset =
+			qdev->dumb_heads[plane->state->crtc->index].x;
+
+	qxl_draw_dirty_fb(qdev, plane->state->fb, bo, 0, 0, &norect, 1, 1,
+			  dumb_shadow_offset);
 }
 
 static void qxl_primary_atomic_disable(struct drm_plane *plane,
@@ -707,12 +715,68 @@ static void qxl_cursor_atomic_disable(struct drm_plane *plane,
 	qxl_release_fence_buffer_objects(release);
 }
 
+static void qxl_update_dumb_head(struct qxl_device *qdev,
+				 int index, struct qxl_bo *bo)
+{
+	uint32_t width, height;
+
+	if (index >= qdev->monitors_config->max_allowed)
+		return;
+
+	if (bo && bo->is_dumb) {
+		width = bo->surf.width;
+		height = bo->surf.height;
+	} else {
+		width = 0;
+		height = 0;
+	}
+
+	if (qdev->dumb_heads[index].width == width &&
+	    qdev->dumb_heads[index].height == height)
+		return;
+
+	DRM_DEBUG("#%d: %dx%d -> %dx%d\n", index,
+		  qdev->dumb_heads[index].width,
+		  qdev->dumb_heads[index].height,
+		  width, height);
+	qdev->dumb_heads[index].width = width;
+	qdev->dumb_heads[index].height = height;
+}
+
+static void qxl_calc_dumb_shadow(struct qxl_device *qdev,
+				 struct qxl_surface *surf)
+{
+	struct qxl_head *head;
+	int i;
+
+	memset(surf, 0, sizeof(*surf));
+	for (i = 0; i < qdev->monitors_config->max_allowed; i++) {
+		head = qdev->dumb_heads + i;
+		head->x = surf->width;
+		surf->width += head->width;
+		if (surf->height < head->height)
+			surf->height = head->height;
+	}
+	if (surf->width < 64)
+		surf->width = 64;
+	if (surf->height < 64)
+		surf->height = 64;
+	surf->format = SPICE_SURFACE_FMT_32_xRGB;
+	surf->stride = surf->width * 4;
+
+	if (!qdev->dumb_shadow_bo ||
+	    qdev->dumb_shadow_bo->surf.width != surf->width ||
+	    qdev->dumb_shadow_bo->surf.height != surf->height)
+		DRM_DEBUG("%dx%d\n", surf->width, surf->height);
+}
+
 static int qxl_plane_prepare_fb(struct drm_plane *plane,
 				struct drm_plane_state *new_state)
 {
 	struct qxl_device *qdev = plane->dev->dev_private;
 	struct drm_gem_object *obj;
-	struct qxl_bo *user_bo, *old_bo = NULL;
+	struct qxl_bo *user_bo;
+	struct qxl_surface surf;
 	int ret;
 
 	if (!new_state->fb)
@@ -722,29 +786,30 @@ static int qxl_plane_prepare_fb(struct drm_plane *plane,
 	user_bo = gem_to_qxl_bo(obj);
 
 	if (plane->type == DRM_PLANE_TYPE_PRIMARY &&
-	    user_bo->is_dumb && !user_bo->shadow) {
-		if (plane->state->fb) {
-			obj = plane->state->fb->obj[0];
-			old_bo = gem_to_qxl_bo(obj);
+	    user_bo->is_dumb) {
+		qxl_update_dumb_head(qdev, new_state->crtc->index,
+				     user_bo);
+		qxl_calc_dumb_shadow(qdev, &surf);
+		if (!qdev->dumb_shadow_bo ||
+		    qdev->dumb_shadow_bo->surf.width  != surf.width ||
+		    qdev->dumb_shadow_bo->surf.height != surf.height) {
+			if (qdev->dumb_shadow_bo) {
+				drm_gem_object_put_unlocked
+					(&qdev->dumb_shadow_bo->gem_base);
+				qdev->dumb_shadow_bo = NULL;
+			}
+			qxl_bo_create(qdev, surf.height * surf.stride,
+				      true, true, QXL_GEM_DOMAIN_SURFACE, &surf,
+				      &qdev->dumb_shadow_bo);
 		}
-		if (old_bo && old_bo->shadow &&
-		    user_bo->gem_base.size == old_bo->gem_base.size &&
-		    plane->state->crtc     == new_state->crtc &&
-		    plane->state->crtc_w   == new_state->crtc_w &&
-		    plane->state->crtc_h   == new_state->crtc_h &&
-		    plane->state->src_x    == new_state->src_x &&
-		    plane->state->src_y    == new_state->src_y &&
-		    plane->state->src_w    == new_state->src_w &&
-		    plane->state->src_h    == new_state->src_h &&
-		    plane->state->rotation == new_state->rotation &&
-		    plane->state->zpos     == new_state->zpos) {
-			drm_gem_object_get(&old_bo->shadow->gem_base);
-			user_bo->shadow = old_bo->shadow;
-		} else {
-			qxl_bo_create(qdev, user_bo->gem_base.size,
-				      true, true, QXL_GEM_DOMAIN_SURFACE, NULL,
-				      &user_bo->shadow);
-			user_bo->shadow->surf = user_bo->surf;
+		if (user_bo->shadow != qdev->dumb_shadow_bo) {
+			if (user_bo->shadow) {
+				drm_gem_object_put_unlocked
+					(&user_bo->shadow->gem_base);
+				user_bo->shadow = NULL;
+			}
+			drm_gem_object_get(&qdev->dumb_shadow_bo->gem_base);
+			user_bo->shadow = qdev->dumb_shadow_bo;
 		}
 	}
 
@@ -773,7 +838,7 @@ static void qxl_plane_cleanup_fb(struct drm_plane *plane,
 	user_bo = gem_to_qxl_bo(obj);
 	qxl_bo_unpin(user_bo);
 
-	if (user_bo->shadow && !user_bo->shadow->is_primary) {
+	if (old_state->fb != plane->state->fb && user_bo->shadow) {
 		drm_gem_object_put_unlocked(&user_bo->shadow->gem_base);
 		user_bo->shadow = NULL;
 	}
@@ -1106,6 +1171,12 @@ int qxl_create_monitors_object(struct qxl_device *qdev)
 
 	memset(qdev->monitors_config, 0, monitors_config_size);
 	qdev->monitors_config->max_allowed = max_allowed;
+
+	qdev->dumb_heads = kcalloc(max_allowed, sizeof(qdev->dumb_heads[0]), GFP_KERNEL);
+	if (!qdev->dumb_heads) {
+		qxl_destroy_monitors_object(qdev);
+		return -ENOMEM;
+	}
 	return 0;
 }