wlroots-hyprland/patches/nvidia-hardware-cursors.patch

This patch fixes hardware cursor rendering for NVIDIA GPUs,
removing the requirement of setting the WLR_NO_HARDWARE_CURSORS
environment variable when using said GPUs. The following comes from:
https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/4596
diff --git a/backend/drm/backend.c b/backend/drm/backend.c
index f91492ac..b16451e0 100644
--- a/backend/drm/backend.c
+++ b/backend/drm/backend.c
@@ -53,9 +53,7 @@ static void backend_destroy(struct wlr_backend *backend) {
 	wl_list_remove(&drm->dev_change.link);
 	wl_list_remove(&drm->dev_remove.link);
 
-	if (drm->parent) {
-		finish_drm_renderer(&drm->mgpu_renderer);
-	}
+	finish_drm_renderer(&drm->mgpu_renderer);
 
 	finish_drm_resources(drm);
 
@@ -224,22 +222,20 @@ struct wlr_backend *wlr_drm_backend_create(struct wlr_session *session,
 		goto error_event;
 	}
 
-	if (drm->parent) {
-		if (!init_drm_renderer(drm, &drm->mgpu_renderer)) {
-			wlr_log(WLR_ERROR, "Failed to initialize renderer");
-			goto error_resources;
-		}
-
-		// We'll perform a multi-GPU copy for all submitted buffers, we need
-		// to be able to texture from them
-		struct wlr_renderer *renderer = drm->mgpu_renderer.wlr_rend;
-		const struct wlr_drm_format_set *texture_formats =
-			wlr_renderer_get_dmabuf_texture_formats(renderer);
-		if (texture_formats == NULL) {
-			wlr_log(WLR_ERROR, "Failed to query renderer texture formats");
-			goto error_mgpu_renderer;
-		}
+	if (!init_drm_renderer(drm, &drm->mgpu_renderer)) {
+		wlr_log(WLR_ERROR, "Failed to initialize renderer");
+		goto error_resources;
+	}
 
+	// We'll perform a multi-GPU copy for all submitted buffers, we need
+	// to be able to texture from them
+	struct wlr_renderer *renderer = drm->mgpu_renderer.wlr_rend;
+	const struct wlr_drm_format_set *texture_formats =
+		wlr_renderer_get_dmabuf_texture_formats(renderer);
+	// Some configurations (alpine CI job) will have a renderer here that does not
+	// support dmabuf formats. We don't want to fail creation of the drm backend
+	// as a result of this, we simply don't populate the format set in that case.
+	if (texture_formats) {
 		// Forbid implicit modifiers, because their meaning changes from one
 		// GPU to another.
 		for (size_t i = 0; i < texture_formats->len; i++) {
@@ -259,8 +255,6 @@ struct wlr_backend *wlr_drm_backend_create(struct wlr_session *session,
 
 	return &drm->backend;
 
-error_mgpu_renderer:
-	finish_drm_renderer(&drm->mgpu_renderer);
 error_resources:
 	finish_drm_resources(drm);
 error_event:
diff --git a/include/render/allocator/gbm.h b/include/render/allocator/gbm.h
index 7e043faf..eb13b3f1 100644
--- a/include/render/allocator/gbm.h
+++ b/include/render/allocator/gbm.h
@@ -12,6 +12,7 @@ struct wlr_gbm_buffer {
 	struct wl_list link; // wlr_gbm_allocator.buffers
 
 	struct gbm_bo *gbm_bo; // NULL if the gbm_device has been destroyed
+	void *gbm_map_data; // NULL unless we have an active mapping
 	struct wlr_dmabuf_attributes dmabuf;
 };
 
diff --git a/render/allocator/gbm.c b/render/allocator/gbm.c
index baa0fb6e..f7946dcc 100644
--- a/render/allocator/gbm.c
+++ b/render/allocator/gbm.c
@@ -171,9 +171,51 @@ static bool buffer_get_dmabuf(struct wlr_buffer *wlr_buffer,
 	return true;
 }
 
+static bool gbm_buffer_begin_data_ptr_access(struct wlr_buffer *wlr_buffer,
+		uint32_t flags, void **data_ptr, uint32_t *format_ptr, size_t *stride_ptr) {
+	struct wlr_gbm_buffer *buffer = get_gbm_buffer_from_buffer(wlr_buffer);
+
+	if (buffer->gbm_bo == NULL) {
+		return false;
+	}
+
+	uint32_t gbm_flags = 0;
+	if (flags & WLR_BUFFER_DATA_PTR_ACCESS_READ) {
+		gbm_flags |= GBM_BO_TRANSFER_READ;
+	}
+	if (flags & WLR_BUFFER_DATA_PTR_ACCESS_WRITE) {
+		gbm_flags |= GBM_BO_TRANSFER_WRITE;
+	}
+
+	uint32_t stride = 0;
+	void *gbm_map_data = NULL;
+	void *data = gbm_bo_map(buffer->gbm_bo, 0, 0,
+		wlr_buffer->width, wlr_buffer->height, gbm_flags, &stride, &gbm_map_data);
+	if (data == NULL) {
+		wlr_log_errno(WLR_ERROR, "gbm_bo_map failed");
+		return false;
+	}
+
+	*data_ptr = data;
+	*format_ptr = buffer->dmabuf.format;
+	*stride_ptr = stride;
+	assert(buffer->gbm_map_data == NULL);
+	buffer->gbm_map_data = gbm_map_data;
+	return true;
+}
+
+static void gbm_buffer_end_data_ptr_access(struct wlr_buffer *wlr_buffer) {
+	struct wlr_gbm_buffer *buffer = get_gbm_buffer_from_buffer(wlr_buffer);
+	assert(buffer->gbm_bo != NULL);
+	gbm_bo_unmap(buffer->gbm_bo, buffer->gbm_map_data);
+	buffer->gbm_map_data = NULL;
+}
+
 static const struct wlr_buffer_impl buffer_impl = {
 	.destroy = buffer_destroy,
 	.get_dmabuf = buffer_get_dmabuf,
+	.begin_data_ptr_access = gbm_buffer_begin_data_ptr_access,
+	.end_data_ptr_access = gbm_buffer_end_data_ptr_access,
 };
 
 static const struct wlr_allocator_interface allocator_impl;
diff --git a/backend/drm/drm.c b/backend/drm/drm.c
index b2e2c392..e23e3be5 100644
--- a/backend/drm/drm.c
+++ b/backend/drm/drm.c
@@ -1005,6 +1005,7 @@ static bool drm_connector_set_cursor(struct wlr_output *output,
 	struct wlr_drm_connector *conn = get_drm_connector_from_output(output);
 	struct wlr_drm_backend *drm = conn->backend;
 	struct wlr_drm_crtc *crtc = conn->crtc;
+	bool ok = false;
 
 	if (!crtc) {
 		return false;
@@ -1033,34 +1034,62 @@ static bool drm_connector_set_cursor(struct wlr_output *output,
 			return false;
 		}
 
-		struct wlr_buffer *local_buf;
-		if (drm->parent) {
+		// First try importing our buffer
+		struct wlr_buffer *local_buf = wlr_buffer_lock(buffer);
+		ok = drm_fb_import(&conn->cursor_pending_fb, drm, local_buf,
+				&plane->formats);
+		wlr_buffer_unlock(local_buf);
+
+		if (!ok) {
+			// If this failed blit a compatible buffer. This will blit it to
+			// our mgpu surface in the case that we are a secondary device
 			struct wlr_drm_format format = {0};
+			// Try to find a common format/modifier
 			if (!drm_plane_pick_render_format(plane, &format, &drm->mgpu_renderer)) {
 				wlr_log(WLR_ERROR, "Failed to pick cursor plane format");
-				return false;
+				// If the above failed it may be because the modifier for this
+				// buffer is not able to be scanned out, as is the case on some
+				// GPUs.  If it failed try to do a linear copy. This will map
+				// the mgpu surface as a linear texture and read pixels from
+				// the buffer into it. This avoids a scenario where the
+				// hardware cannot render to linear textures but only linear
+				// textures are supported for cursors, as is the case with
+				// Nvidia and VmWare GPUs
+
+				// Create a default format with only the linear modifier
+				wlr_drm_format_init(&format, DRM_FORMAT_ARGB8888);
+				if (!wlr_drm_format_add(&format, 0)) {
+					wlr_drm_format_finish(&format);
+					return false;
+				}
 			}
 
-			bool ok = init_drm_surface(&plane->mgpu_surf, &drm->mgpu_renderer,
-				buffer->width, buffer->height, &format);
+			ok = init_drm_surface(&plane->mgpu_surf, &drm->mgpu_renderer,
+					buffer->width, buffer->height, &format);
 			wlr_drm_format_finish(&format);
 			if (!ok) {
 				return false;
 			}
 
+			// First try to blit our cursor image.
 			local_buf = drm_surface_blit(&plane->mgpu_surf, buffer);
+			// If this is not possible due to the GPU not being able to
+			// render to a supported cursor format, then fall back to a
+			// more expensive copy
 			if (local_buf == NULL) {
-				return false;
+				// use the primary GPU for this, which will either be the current DRM
+				// backend or the parent if it has one
+				struct wlr_drm_renderer *drm_renderer =
+					drm->parent ? &drm->parent->mgpu_renderer : &drm->mgpu_renderer;
+				local_buf = drm_cursor_copy(&plane->mgpu_surf, drm_renderer, buffer);
+				if (local_buf == NULL) {
+					return false;
+				}
 			}
-		} else {
-			local_buf = wlr_buffer_lock(buffer);
-		}
 
-		bool ok = drm_fb_import(&conn->cursor_pending_fb, drm, local_buf,
-			&plane->formats);
-		wlr_buffer_unlock(local_buf);
-		if (!ok) {
-			return false;
+			ok = drm_fb_import(&conn->cursor_pending_fb, drm, local_buf,
+					&plane->formats);
+			wlr_buffer_unlock(local_buf);
 		}
 
 		conn->cursor_enabled = true;
@@ -1069,7 +1098,7 @@ static bool drm_connector_set_cursor(struct wlr_output *output,
 	}
 
 	wlr_output_update_needs_frame(output);
-	return true;
+	return ok;
 }
 
 static bool drm_connector_move_cursor(struct wlr_output *output,
diff --git a/backend/drm/renderer.c b/backend/drm/renderer.c
index e4aadc10..07ec5a52 100644
--- a/backend/drm/renderer.c
+++ b/backend/drm/renderer.c
@@ -1,4 +1,5 @@
 #include <assert.h>
+#include <stdlib.h>
 #include <drm_fourcc.h>
 #include <wlr/render/swapchain.h>
 #include <wlr/render/wlr_renderer.h>
@@ -73,6 +74,82 @@ bool init_drm_surface(struct wlr_drm_surface *surf,
 	return true;
 }
 
+struct wlr_buffer *drm_cursor_copy(struct wlr_drm_surface *surf,
+		struct wlr_drm_renderer *parent_renderer, struct wlr_buffer *buffer) {
+	void *data, *src_data;
+	size_t stride, src_stride;
+	uint32_t drm_format = DRM_FORMAT_ARGB8888;
+
+	if (surf->swapchain->width != buffer->width ||
+			surf->swapchain->height != buffer->height) {
+		wlr_log(WLR_ERROR, "Surface size doesn't match buffer size");
+		return NULL;
+	}
+
+	struct wlr_texture *tex = wlr_texture_from_buffer(parent_renderer->wlr_rend, buffer);
+	if (tex == NULL) {
+		wlr_log(WLR_ERROR, "Failed to import cursor into multi-GPU renderer");
+		return NULL;
+	}
+
+	struct wlr_buffer *dst = wlr_swapchain_acquire(surf->swapchain, NULL);
+	if (!dst) {
+		wlr_log(WLR_ERROR, "Failed to acquire multi-GPU swapchain buffer");
+		goto error_tex;
+	}
+
+	if (!wlr_buffer_begin_data_ptr_access(dst, WLR_BUFFER_DATA_PTR_ACCESS_WRITE, &data,
+				&drm_format, &stride)) {
+		wlr_log(WLR_ERROR, "Failed to get data ptr access to DRM cursor surface");
+		goto error_dst;
+	}
+
+	// Allocate memory to store our pixel data
+	src_stride = tex->width * 4;
+	src_data = malloc(tex->height * src_stride);
+	if (data == NULL) {
+		goto end_access;
+	}
+
+	// Get our linear pixel data from the source texture
+	bool result = wlr_texture_read_pixels(tex, &(struct wlr_texture_read_pixels_options) {
+		.format = DRM_FORMAT_ARGB8888,
+		.stride = src_stride,
+		.data = src_data,
+	});
+
+	if (!result) {
+		wlr_log(WLR_ERROR, "Failed to get data ptr access to DRM cursor surface");
+		goto free_src_data;
+	}
+
+	if (stride != src_stride) {
+		wlr_log(WLR_ERROR, "Format/stride values for DRM cursor source and destination"
+				"buffers do not match");
+		goto free_src_data;
+	}
+
+	// Copy our linear pixels into our DRM surface
+	memcpy(data, src_data, stride * buffer->height);
+
+	free(src_data);
+	wlr_buffer_end_data_ptr_access(dst);
+	wlr_texture_destroy(tex);
+
+	return dst;
+
+free_src_data:
+	free(src_data);
+end_access:
+	wlr_buffer_end_data_ptr_access(dst);
+error_dst:
+	wlr_buffer_unlock(dst);
+error_tex:
+	wlr_texture_destroy(tex);
+
+	return NULL;
+}
+
 struct wlr_buffer *drm_surface_blit(struct wlr_drm_surface *surf,
 		struct wlr_buffer *buffer) {
 	struct wlr_renderer *renderer = surf->renderer->wlr_rend;
diff --git a/include/backend/drm/renderer.h b/include/backend/drm/renderer.h
index f53f720b..115d49f3 100644
--- a/include/backend/drm/renderer.h
+++ b/include/backend/drm/renderer.h
@@ -33,6 +33,8 @@ void finish_drm_surface(struct wlr_drm_surface *surf);
 
 struct wlr_buffer *drm_surface_blit(struct wlr_drm_surface *surf,
 	struct wlr_buffer *buffer);
+struct wlr_buffer *drm_cursor_copy(struct wlr_drm_surface *surf,
+	struct wlr_drm_renderer *parent_renderer, struct wlr_buffer *buffer);
 
 bool drm_plane_pick_render_format(struct wlr_drm_plane *plane,
 	struct wlr_drm_format *fmt, struct wlr_drm_renderer *renderer);
diff --git a/types/output/cursor.c b/types/output/cursor.c
index 22654b0a..ee9a195f 100644
--- a/types/output/cursor.c
+++ b/types/output/cursor.c
@@ -171,7 +171,17 @@ static bool output_pick_cursor_format(struct wlr_output *output,
 		}
 	}
 
-	return output_pick_format(output, display_formats, format, DRM_FORMAT_ARGB8888);
+
+	// If this fails to find a shared modifier try to use a linear
+	// modifier. This avoids a scenario where the hardware cannot render to
+	// linear textures but only linear textures are supported for cursors,
+	// as is the case with Nvidia and VmWare GPUs
+	if (!output_pick_format(output, display_formats, format, DRM_FORMAT_ARGB8888)) {
+		// Clear the format as output_pick_format doesn't zero it
+		memset(format, 0, sizeof(*format));
+		return output_pick_format(output, NULL, format, DRM_FORMAT_ARGB8888);
+	}
+	return true;
 }
 
 static struct wlr_buffer *render_cursor_buffer(struct wlr_output_cursor *cursor) {