[RFC 1/3] fbdev: hyperv_fb: Remove hyperv_fb driver

[RFC 1/3] fbdev: hyperv_fb: Remove hyperv_fb driver

[Prasanna Kumar T S M]

The Hyper-V DRM driver is available since kernel version 5.14 and
provides full KMS support along with fbdev emulation via the DRM fbdev
helpers. This makes the hyperv_fb driver redundant, remove it.

Signed-off-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com>
---
 MAINTAINERS                     |    1 -
 drivers/video/fbdev/Kconfig     |    8 -
 drivers/video/fbdev/Makefile    |    1 -
 drivers/video/fbdev/hyperv_fb.c | 1386 -------------------------------
 4 files changed, 1396 deletions(-)
 delete mode 100644 drivers/video/fbdev/hyperv_fb.c

diff --git a/MAINTAINERS b/MAINTAINERS
index e94d68c980c5..9d0f0e929356 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11416,7 +11416,6 @@ F:	drivers/pci/controller/pci-hyperv-intf.c
 F:	drivers/pci/controller/pci-hyperv.c
 F:	drivers/scsi/storvsc_drv.c
 F:	drivers/uio/uio_hv_generic.c
-F:	drivers/video/fbdev/hyperv_fb.c
 F:	include/asm-generic/mshyperv.h
 F:	include/clocksource/hyperv_timer.h
 F:	include/hyperv/hvgdk.h
diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig
index c21484d15f0c..bb8ac759f6aa 100644
--- a/drivers/video/fbdev/Kconfig
+++ b/drivers/video/fbdev/Kconfig
@@ -1772,14 +1772,6 @@ config FB_BROADSHEET
 	  and could also have been called by other names when coupled with
 	  a bridge adapter.
 
-config FB_HYPERV
-	tristate "Microsoft Hyper-V Synthetic Video support"
-	depends on FB && HYPERV
-	select DMA_CMA if HAVE_DMA_CONTIGUOUS && CMA
-	select FB_IOMEM_HELPERS_DEFERRED
-	help
-	  This framebuffer driver supports Microsoft Hyper-V Synthetic Video.
-
 config FB_SIMPLE
 	tristate "Simple framebuffer support"
 	depends on FB
diff --git a/drivers/video/fbdev/Makefile b/drivers/video/fbdev/Makefile
index b3d12f977c06..36a18d958ba0 100644
--- a/drivers/video/fbdev/Makefile
+++ b/drivers/video/fbdev/Makefile
@@ -111,7 +111,6 @@ obj-y                             += omap2/
 obj-$(CONFIG_XEN_FBDEV_FRONTEND)  += xen-fbfront.o
 obj-$(CONFIG_FB_CARMINE)          += carminefb.o
 obj-$(CONFIG_FB_MB862XX)	  += mb862xx/
-obj-$(CONFIG_FB_HYPERV)		  += hyperv_fb.o
 obj-$(CONFIG_FB_OPENCORES)	  += ocfb.o
 obj-$(CONFIG_FB_SM712)		  += sm712fb.o
 
diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
deleted file mode 100644
index 75338ffc703f..000000000000
--- a/drivers/video/fbdev/hyperv_fb.c
+++ /dev/null
@@ -1,1386 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Copyright (c) 2012, Microsoft Corporation.
- *
- * Author:
- *   Haiyang Zhang <haiyangz@microsoft.com>
- */
-
-/*
- * Hyper-V Synthetic Video Frame Buffer Driver
- *
- * This is the driver for the Hyper-V Synthetic Video, which supports
- * screen resolution up to Full HD 1920x1080 with 32 bit color on Windows
- * Server 2012, and 1600x1200 with 16 bit color on Windows Server 2008 R2
- * or earlier.
- *
- * It also solves the double mouse cursor issue of the emulated video mode.
- *
- * The default screen resolution is 1152x864, which may be changed by a
- * kernel parameter:
- *     video=hyperv_fb:<width>x<height>
- *     For example: video=hyperv_fb:1280x1024
- *
- * Portrait orientation is also supported:
- *     For example: video=hyperv_fb:864x1152
- *
- * When a Windows 10 RS5+ host is used, the virtual machine screen
- * resolution is obtained from the host. The "video=hyperv_fb" option is
- * not needed, but still can be used to overwrite what the host specifies.
- * The VM resolution on the host could be set by executing the powershell
- * "set-vmvideo" command. For example
- *     set-vmvideo -vmname name -horizontalresolution:1920 \
- * -verticalresolution:1200 -resolutiontype single
- *
- * Gen 1 VMs also support direct using VM's physical memory for framebuffer.
- * It could improve the efficiency and performance for framebuffer and VM.
- * This requires to allocate contiguous physical memory from Linux kernel's
- * CMA memory allocator. To enable this, supply a kernel parameter to give
- * enough memory space to CMA allocator for framebuffer. For example:
- *    cma=130m
- * This gives 130MB memory to CMA allocator that can be allocated to
- * framebuffer. For reference, 8K resolution (7680x4320) takes about
- * 127MB memory.
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/aperture.h>
-#include <linux/module.h>
-#include <linux/kernel.h>
-#include <linux/vmalloc.h>
-#include <linux/init.h>
-#include <linux/completion.h>
-#include <linux/fb.h>
-#include <linux/pci.h>
-#include <linux/panic_notifier.h>
-#include <linux/efi.h>
-#include <linux/console.h>
-
-#include <linux/hyperv.h>
-
-/* Hyper-V Synthetic Video Protocol definitions and structures */
-#define MAX_VMBUS_PKT_SIZE 0x4000
-
-#define SYNTHVID_VERSION(major, minor) ((minor) << 16 | (major))
-/* Support for VERSION_WIN7 is removed. #define is retained for reference. */
-#define SYNTHVID_VERSION_WIN7 SYNTHVID_VERSION(3, 0)
-#define SYNTHVID_VERSION_WIN8 SYNTHVID_VERSION(3, 2)
-#define SYNTHVID_VERSION_WIN10 SYNTHVID_VERSION(3, 5)
-
-#define SYNTHVID_VER_GET_MAJOR(ver) (ver & 0x0000ffff)
-#define SYNTHVID_VER_GET_MINOR(ver) ((ver & 0xffff0000) >> 16)
-
-#define SYNTHVID_DEPTH_WIN8 32
-#define SYNTHVID_FB_SIZE_WIN8 (8 * 1024 * 1024)
-
-enum pipe_msg_type {
-	PIPE_MSG_INVALID,
-	PIPE_MSG_DATA,
-	PIPE_MSG_MAX
-};
-
-struct pipe_msg_hdr {
-	u32 type;
-	u32 size; /* size of message after this field */
-} __packed;
-
-
-enum synthvid_msg_type {
-	SYNTHVID_ERROR			= 0,
-	SYNTHVID_VERSION_REQUEST	= 1,
-	SYNTHVID_VERSION_RESPONSE	= 2,
-	SYNTHVID_VRAM_LOCATION		= 3,
-	SYNTHVID_VRAM_LOCATION_ACK	= 4,
-	SYNTHVID_SITUATION_UPDATE	= 5,
-	SYNTHVID_SITUATION_UPDATE_ACK	= 6,
-	SYNTHVID_POINTER_POSITION	= 7,
-	SYNTHVID_POINTER_SHAPE		= 8,
-	SYNTHVID_FEATURE_CHANGE		= 9,
-	SYNTHVID_DIRT			= 10,
-	SYNTHVID_RESOLUTION_REQUEST	= 13,
-	SYNTHVID_RESOLUTION_RESPONSE	= 14,
-
-	SYNTHVID_MAX			= 15
-};
-
-#define		SYNTHVID_EDID_BLOCK_SIZE	128
-#define		SYNTHVID_MAX_RESOLUTION_COUNT	64
-
-struct hvd_screen_info {
-	u16 width;
-	u16 height;
-} __packed;
-
-struct synthvid_msg_hdr {
-	u32 type;
-	u32 size;  /* size of this header + payload after this field*/
-} __packed;
-
-struct synthvid_version_req {
-	u32 version;
-} __packed;
-
-struct synthvid_version_resp {
-	u32 version;
-	u8 is_accepted;
-	u8 max_video_outputs;
-} __packed;
-
-struct synthvid_supported_resolution_req {
-	u8 maximum_resolution_count;
-} __packed;
-
-struct synthvid_supported_resolution_resp {
-	u8 edid_block[SYNTHVID_EDID_BLOCK_SIZE];
-	u8 resolution_count;
-	u8 default_resolution_index;
-	u8 is_standard;
-	struct hvd_screen_info
-		supported_resolution[SYNTHVID_MAX_RESOLUTION_COUNT];
-} __packed;
-
-struct synthvid_vram_location {
-	u64 user_ctx;
-	u8 is_vram_gpa_specified;
-	u64 vram_gpa;
-} __packed;
-
-struct synthvid_vram_location_ack {
-	u64 user_ctx;
-} __packed;
-
-struct video_output_situation {
-	u8 active;
-	u32 vram_offset;
-	u8 depth_bits;
-	u32 width_pixels;
-	u32 height_pixels;
-	u32 pitch_bytes;
-} __packed;
-
-struct synthvid_situation_update {
-	u64 user_ctx;
-	u8 video_output_count;
-	struct video_output_situation video_output[1];
-} __packed;
-
-struct synthvid_situation_update_ack {
-	u64 user_ctx;
-} __packed;
-
-struct synthvid_pointer_position {
-	u8 is_visible;
-	u8 video_output;
-	s32 image_x;
-	s32 image_y;
-} __packed;
-
-
-#define CURSOR_MAX_X 96
-#define CURSOR_MAX_Y 96
-#define CURSOR_ARGB_PIXEL_SIZE 4
-#define CURSOR_MAX_SIZE (CURSOR_MAX_X * CURSOR_MAX_Y * CURSOR_ARGB_PIXEL_SIZE)
-#define CURSOR_COMPLETE (-1)
-
-struct synthvid_pointer_shape {
-	u8 part_idx;
-	u8 is_argb;
-	u32 width; /* CURSOR_MAX_X at most */
-	u32 height; /* CURSOR_MAX_Y at most */
-	u32 hot_x; /* hotspot relative to upper-left of pointer image */
-	u32 hot_y;
-	u8 data[4];
-} __packed;
-
-struct synthvid_feature_change {
-	u8 is_dirt_needed;
-	u8 is_ptr_pos_needed;
-	u8 is_ptr_shape_needed;
-	u8 is_situ_needed;
-} __packed;
-
-struct rect {
-	s32 x1, y1; /* top left corner */
-	s32 x2, y2; /* bottom right corner, exclusive */
-} __packed;
-
-struct synthvid_dirt {
-	u8 video_output;
-	u8 dirt_count;
-	struct rect rect[1];
-} __packed;
-
-struct synthvid_msg {
-	struct pipe_msg_hdr pipe_hdr;
-	struct synthvid_msg_hdr vid_hdr;
-	union {
-		struct synthvid_version_req ver_req;
-		struct synthvid_version_resp ver_resp;
-		struct synthvid_vram_location vram;
-		struct synthvid_vram_location_ack vram_ack;
-		struct synthvid_situation_update situ;
-		struct synthvid_situation_update_ack situ_ack;
-		struct synthvid_pointer_position ptr_pos;
-		struct synthvid_pointer_shape ptr_shape;
-		struct synthvid_feature_change feature_chg;
-		struct synthvid_dirt dirt;
-		struct synthvid_supported_resolution_req resolution_req;
-		struct synthvid_supported_resolution_resp resolution_resp;
-	};
-} __packed;
-
-
-/* FB driver definitions and structures */
-#define HVFB_WIDTH 1152 /* default screen width */
-#define HVFB_HEIGHT 864 /* default screen height */
-#define HVFB_WIDTH_MIN 640
-#define HVFB_HEIGHT_MIN 480
-
-#define RING_BUFSIZE (256 * 1024)
-#define VSP_TIMEOUT (10 * HZ)
-#define HVFB_UPDATE_DELAY (HZ / 20)
-#define HVFB_ONDEMAND_THROTTLE (HZ / 20)
-
-struct hvfb_par {
-	struct fb_info *info;
-	struct resource *mem;
-	bool fb_ready; /* fb device is ready */
-	struct completion wait;
-	u32 synthvid_version;
-
-	struct delayed_work dwork;
-	bool update;
-	bool update_saved; /* The value of 'update' before hibernation */
-
-	u32 pseudo_palette[16];
-	u8 init_buf[MAX_VMBUS_PKT_SIZE];
-	u8 recv_buf[MAX_VMBUS_PKT_SIZE];
-
-	/* If true, the VSC notifies the VSP on every framebuffer change */
-	bool synchronous_fb;
-
-	/* If true, need to copy from deferred IO mem to framebuffer mem */
-	bool need_docopy;
-
-	struct notifier_block hvfb_panic_nb;
-
-	/* Memory for deferred IO and frame buffer itself */
-	unsigned char *dio_vp;
-	unsigned char *mmio_vp;
-	phys_addr_t mmio_pp;
-
-	/* Dirty rectangle, protected by delayed_refresh_lock */
-	int x1, y1, x2, y2;
-	bool delayed_refresh;
-	spinlock_t delayed_refresh_lock;
-};
-
-static uint screen_width = HVFB_WIDTH;
-static uint screen_height = HVFB_HEIGHT;
-static uint screen_depth;
-static uint screen_fb_size;
-static uint dio_fb_size; /* FB size for deferred IO */
-
-static void hvfb_putmem(struct fb_info *info);
-
-/* Send message to Hyper-V host */
-static inline int synthvid_send(struct hv_device *hdev,
-				struct synthvid_msg *msg)
-{
-	static atomic64_t request_id = ATOMIC64_INIT(0);
-	int ret;
-
-	msg->pipe_hdr.type = PIPE_MSG_DATA;
-	msg->pipe_hdr.size = msg->vid_hdr.size;
-
-	ret = vmbus_sendpacket(hdev->channel, msg,
-			       msg->vid_hdr.size + sizeof(struct pipe_msg_hdr),
-			       atomic64_inc_return(&request_id),
-			       VM_PKT_DATA_INBAND, 0);
-
-	if (ret)
-		pr_err_ratelimited("Unable to send packet via vmbus; error %d\n", ret);
-
-	return ret;
-}
-
-
-/* Send screen resolution info to host */
-static int synthvid_send_situ(struct hv_device *hdev)
-{
-	struct fb_info *info = hv_get_drvdata(hdev);
-	struct synthvid_msg msg;
-
-	if (!info)
-		return -ENODEV;
-
-	memset(&msg, 0, sizeof(struct synthvid_msg));
-
-	msg.vid_hdr.type = SYNTHVID_SITUATION_UPDATE;
-	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
-		sizeof(struct synthvid_situation_update);
-	msg.situ.user_ctx = 0;
-	msg.situ.video_output_count = 1;
-	msg.situ.video_output[0].active = 1;
-	msg.situ.video_output[0].vram_offset = 0;
-	msg.situ.video_output[0].depth_bits = info->var.bits_per_pixel;
-	msg.situ.video_output[0].width_pixels = info->var.xres;
-	msg.situ.video_output[0].height_pixels = info->var.yres;
-	msg.situ.video_output[0].pitch_bytes = info->fix.line_length;
-
-	synthvid_send(hdev, &msg);
-
-	return 0;
-}
-
-/* Send mouse pointer info to host */
-static int synthvid_send_ptr(struct hv_device *hdev)
-{
-	struct synthvid_msg msg;
-
-	memset(&msg, 0, sizeof(struct synthvid_msg));
-	msg.vid_hdr.type = SYNTHVID_POINTER_POSITION;
-	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
-		sizeof(struct synthvid_pointer_position);
-	msg.ptr_pos.is_visible = 1;
-	msg.ptr_pos.video_output = 0;
-	msg.ptr_pos.image_x = 0;
-	msg.ptr_pos.image_y = 0;
-	synthvid_send(hdev, &msg);
-
-	memset(&msg, 0, sizeof(struct synthvid_msg));
-	msg.vid_hdr.type = SYNTHVID_POINTER_SHAPE;
-	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
-		sizeof(struct synthvid_pointer_shape);
-	msg.ptr_shape.part_idx = CURSOR_COMPLETE;
-	msg.ptr_shape.is_argb = 1;
-	msg.ptr_shape.width = 1;
-	msg.ptr_shape.height = 1;
-	msg.ptr_shape.hot_x = 0;
-	msg.ptr_shape.hot_y = 0;
-	msg.ptr_shape.data[0] = 0;
-	msg.ptr_shape.data[1] = 1;
-	msg.ptr_shape.data[2] = 1;
-	msg.ptr_shape.data[3] = 1;
-	synthvid_send(hdev, &msg);
-
-	return 0;
-}
-
-/* Send updated screen area (dirty rectangle) location to host */
-static int
-synthvid_update(struct fb_info *info, int x1, int y1, int x2, int y2)
-{
-	struct hv_device *hdev = device_to_hv_device(info->device);
-	struct synthvid_msg msg;
-
-	memset(&msg, 0, sizeof(struct synthvid_msg));
-	if (x2 == INT_MAX)
-		x2 = info->var.xres;
-	if (y2 == INT_MAX)
-		y2 = info->var.yres;
-
-	msg.vid_hdr.type = SYNTHVID_DIRT;
-	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
-		sizeof(struct synthvid_dirt);
-	msg.dirt.video_output = 0;
-	msg.dirt.dirt_count = 1;
-	msg.dirt.rect[0].x1 = (x1 > x2) ? 0 : x1;
-	msg.dirt.rect[0].y1 = (y1 > y2) ? 0 : y1;
-	msg.dirt.rect[0].x2 =
-		(x2 < x1 || x2 > info->var.xres) ? info->var.xres : x2;
-	msg.dirt.rect[0].y2 =
-		(y2 < y1 || y2 > info->var.yres) ? info->var.yres : y2;
-
-	synthvid_send(hdev, &msg);
-
-	return 0;
-}
-
-static void hvfb_docopy(struct hvfb_par *par,
-			unsigned long offset,
-			unsigned long size)
-{
-	if (!par || !par->mmio_vp || !par->dio_vp || !par->fb_ready ||
-	    size == 0 || offset >= dio_fb_size)
-		return;
-
-	if (offset + size > dio_fb_size)
-		size = dio_fb_size - offset;
-
-	memcpy(par->mmio_vp + offset, par->dio_vp + offset, size);
-}
-
-/* Deferred IO callback */
-static void synthvid_deferred_io(struct fb_info *p, struct list_head *pagereflist)
-{
-	struct hvfb_par *par = p->par;
-	struct fb_deferred_io_pageref *pageref;
-	unsigned long start, end;
-	int y1, y2, miny, maxy;
-
-	miny = INT_MAX;
-	maxy = 0;
-
-	/*
-	 * Merge dirty pages. It is possible that last page cross
-	 * over the end of frame buffer row yres. This is taken care of
-	 * in synthvid_update function by clamping the y2
-	 * value to yres.
-	 */
-	list_for_each_entry(pageref, pagereflist, list) {
-		start = pageref->offset;
-		end = start + PAGE_SIZE - 1;
-		y1 = start / p->fix.line_length;
-		y2 = end / p->fix.line_length;
-		miny = min_t(int, miny, y1);
-		maxy = max_t(int, maxy, y2);
-
-		/* Copy from dio space to mmio address */
-		if (par->fb_ready && par->need_docopy)
-			hvfb_docopy(par, start, PAGE_SIZE);
-	}
-
-	if (par->fb_ready && par->update)
-		synthvid_update(p, 0, miny, p->var.xres, maxy + 1);
-}
-
-static struct fb_deferred_io synthvid_defio = {
-	.delay		= HZ / 20,
-	.deferred_io	= synthvid_deferred_io,
-};
-
-/*
- * Actions on received messages from host:
- * Complete the wait event.
- * Or, reply with screen and cursor info.
- */
-static void synthvid_recv_sub(struct hv_device *hdev)
-{
-	struct fb_info *info = hv_get_drvdata(hdev);
-	struct hvfb_par *par;
-	struct synthvid_msg *msg;
-
-	if (!info)
-		return;
-
-	par = info->par;
-	msg = (struct synthvid_msg *)par->recv_buf;
-
-	/* Complete the wait event */
-	if (msg->vid_hdr.type == SYNTHVID_VERSION_RESPONSE ||
-	    msg->vid_hdr.type == SYNTHVID_RESOLUTION_RESPONSE ||
-	    msg->vid_hdr.type == SYNTHVID_VRAM_LOCATION_ACK) {
-		memcpy(par->init_buf, msg, MAX_VMBUS_PKT_SIZE);
-		complete(&par->wait);
-		return;
-	}
-
-	/* Reply with screen and cursor info */
-	if (msg->vid_hdr.type == SYNTHVID_FEATURE_CHANGE) {
-		if (par->fb_ready) {
-			synthvid_send_ptr(hdev);
-			synthvid_send_situ(hdev);
-		}
-
-		par->update = msg->feature_chg.is_dirt_needed;
-		if (par->update)
-			schedule_delayed_work(&par->dwork, HVFB_UPDATE_DELAY);
-	}
-}
-
-/* Receive callback for messages from the host */
-static void synthvid_receive(void *ctx)
-{
-	struct hv_device *hdev = ctx;
-	struct fb_info *info = hv_get_drvdata(hdev);
-	struct hvfb_par *par;
-	struct synthvid_msg *recv_buf;
-	u32 bytes_recvd;
-	u64 req_id;
-	int ret;
-
-	if (!info)
-		return;
-
-	par = info->par;
-	recv_buf = (struct synthvid_msg *)par->recv_buf;
-
-	do {
-		ret = vmbus_recvpacket(hdev->channel, recv_buf,
-				       MAX_VMBUS_PKT_SIZE,
-				       &bytes_recvd, &req_id);
-		if (bytes_recvd > 0 &&
-		    recv_buf->pipe_hdr.type == PIPE_MSG_DATA)
-			synthvid_recv_sub(hdev);
-	} while (bytes_recvd > 0 && ret == 0);
-}
-
-/* Check if the ver1 version is equal or greater than ver2 */
-static inline bool synthvid_ver_ge(u32 ver1, u32 ver2)
-{
-	if (SYNTHVID_VER_GET_MAJOR(ver1) > SYNTHVID_VER_GET_MAJOR(ver2) ||
-	    (SYNTHVID_VER_GET_MAJOR(ver1) == SYNTHVID_VER_GET_MAJOR(ver2) &&
-	     SYNTHVID_VER_GET_MINOR(ver1) >= SYNTHVID_VER_GET_MINOR(ver2)))
-		return true;
-
-	return false;
-}
-
-/* Check synthetic video protocol version with the host */
-static int synthvid_negotiate_ver(struct hv_device *hdev, u32 ver)
-{
-	struct fb_info *info = hv_get_drvdata(hdev);
-	struct hvfb_par *par = info->par;
-	struct synthvid_msg *msg = (struct synthvid_msg *)par->init_buf;
-	int ret = 0;
-	unsigned long t;
-
-	memset(msg, 0, sizeof(struct synthvid_msg));
-	msg->vid_hdr.type = SYNTHVID_VERSION_REQUEST;
-	msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
-		sizeof(struct synthvid_version_req);
-	msg->ver_req.version = ver;
-	synthvid_send(hdev, msg);
-
-	t = wait_for_completion_timeout(&par->wait, VSP_TIMEOUT);
-	if (!t) {
-		pr_err("Time out on waiting version response\n");
-		ret = -ETIMEDOUT;
-		goto out;
-	}
-	if (!msg->ver_resp.is_accepted) {
-		ret = -ENODEV;
-		goto out;
-	}
-
-	par->synthvid_version = ver;
-	pr_info("Synthvid Version major %d, minor %d\n",
-		SYNTHVID_VER_GET_MAJOR(ver), SYNTHVID_VER_GET_MINOR(ver));
-
-out:
-	return ret;
-}
-
-/* Get current resolution from the host */
-static int synthvid_get_supported_resolution(struct hv_device *hdev)
-{
-	struct fb_info *info = hv_get_drvdata(hdev);
-	struct hvfb_par *par = info->par;
-	struct synthvid_msg *msg = (struct synthvid_msg *)par->init_buf;
-	int ret = 0;
-	unsigned long t;
-	u8 index;
-
-	memset(msg, 0, sizeof(struct synthvid_msg));
-	msg->vid_hdr.type = SYNTHVID_RESOLUTION_REQUEST;
-	msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
-		sizeof(struct synthvid_supported_resolution_req);
-
-	msg->resolution_req.maximum_resolution_count =
-		SYNTHVID_MAX_RESOLUTION_COUNT;
-	synthvid_send(hdev, msg);
-
-	t = wait_for_completion_timeout(&par->wait, VSP_TIMEOUT);
-	if (!t) {
-		pr_err("Time out on waiting resolution response\n");
-		ret = -ETIMEDOUT;
-		goto out;
-	}
-
-	if (msg->resolution_resp.resolution_count == 0) {
-		pr_err("No supported resolutions\n");
-		ret = -ENODEV;
-		goto out;
-	}
-
-	index = msg->resolution_resp.default_resolution_index;
-	if (index >= msg->resolution_resp.resolution_count) {
-		pr_err("Invalid resolution index: %d\n", index);
-		ret = -ENODEV;
-		goto out;
-	}
-
-	screen_width =
-		msg->resolution_resp.supported_resolution[index].width;
-	screen_height =
-		msg->resolution_resp.supported_resolution[index].height;
-
-out:
-	return ret;
-}
-
-/* Connect to VSP (Virtual Service Provider) on host */
-static int synthvid_connect_vsp(struct hv_device *hdev)
-{
-	struct fb_info *info = hv_get_drvdata(hdev);
-	struct hvfb_par *par = info->par;
-	int ret;
-
-	ret = vmbus_open(hdev->channel, RING_BUFSIZE, RING_BUFSIZE,
-			 NULL, 0, synthvid_receive, hdev);
-	if (ret) {
-		pr_err("Unable to open vmbus channel\n");
-		return ret;
-	}
-
-	/* Negotiate the protocol version with host */
-	switch (vmbus_proto_version) {
-	case VERSION_WIN10:
-	case VERSION_WIN10_V5:
-		ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN10);
-		if (!ret)
-			break;
-		fallthrough;
-	case VERSION_WIN8:
-	case VERSION_WIN8_1:
-		ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN8);
-		break;
-	default:
-		ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN10);
-		break;
-	}
-
-	if (ret) {
-		pr_err("Synthetic video device version not accepted\n");
-		goto error;
-	}
-
-	screen_depth = SYNTHVID_DEPTH_WIN8;
-	if (synthvid_ver_ge(par->synthvid_version, SYNTHVID_VERSION_WIN10)) {
-		ret = synthvid_get_supported_resolution(hdev);
-		if (ret)
-			pr_info("Failed to get supported resolution from host, use default\n");
-	}
-
-	screen_fb_size = hdev->channel->offermsg.offer.
-				mmio_megabytes * 1024 * 1024;
-
-	return 0;
-
-error:
-	vmbus_close(hdev->channel);
-	return ret;
-}
-
-/* Send VRAM and Situation messages to the host */
-static int synthvid_send_config(struct hv_device *hdev)
-{
-	struct fb_info *info = hv_get_drvdata(hdev);
-	struct hvfb_par *par = info->par;
-	struct synthvid_msg *msg = (struct synthvid_msg *)par->init_buf;
-	int ret = 0;
-	unsigned long t;
-
-	/* Send VRAM location */
-	memset(msg, 0, sizeof(struct synthvid_msg));
-	msg->vid_hdr.type = SYNTHVID_VRAM_LOCATION;
-	msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
-		sizeof(struct synthvid_vram_location);
-	msg->vram.user_ctx = msg->vram.vram_gpa = par->mmio_pp;
-	msg->vram.is_vram_gpa_specified = 1;
-	synthvid_send(hdev, msg);
-
-	t = wait_for_completion_timeout(&par->wait, VSP_TIMEOUT);
-	if (!t) {
-		pr_err("Time out on waiting vram location ack\n");
-		ret = -ETIMEDOUT;
-		goto out;
-	}
-	if (msg->vram_ack.user_ctx != par->mmio_pp) {
-		pr_err("Unable to set VRAM location\n");
-		ret = -ENODEV;
-		goto out;
-	}
-
-	/* Send pointer and situation update */
-	synthvid_send_ptr(hdev);
-	synthvid_send_situ(hdev);
-
-out:
-	return ret;
-}
-
-
-/*
- * Delayed work callback:
- * It is scheduled to call whenever update request is received and it has
- * not been called in last HVFB_ONDEMAND_THROTTLE time interval.
- */
-static void hvfb_update_work(struct work_struct *w)
-{
-	struct hvfb_par *par = container_of(w, struct hvfb_par, dwork.work);
-	struct fb_info *info = par->info;
-	unsigned long flags;
-	int x1, x2, y1, y2;
-	int j;
-
-	spin_lock_irqsave(&par->delayed_refresh_lock, flags);
-	/* Reset the request flag */
-	par->delayed_refresh = false;
-
-	/* Store the dirty rectangle to local variables */
-	x1 = par->x1;
-	x2 = par->x2;
-	y1 = par->y1;
-	y2 = par->y2;
-
-	/* Clear dirty rectangle */
-	par->x1 = par->y1 = INT_MAX;
-	par->x2 = par->y2 = 0;
-
-	spin_unlock_irqrestore(&par->delayed_refresh_lock, flags);
-
-	if (x1 > info->var.xres || x2 > info->var.xres ||
-	    y1 > info->var.yres || y2 > info->var.yres || x2 <= x1)
-		return;
-
-	/* Copy the dirty rectangle to frame buffer memory */
-	if (par->need_docopy)
-		for (j = y1; j < y2; j++)
-			hvfb_docopy(par,
-				    j * info->fix.line_length +
-				    (x1 * screen_depth / 8),
-				    (x2 - x1) * screen_depth / 8);
-
-	/* Refresh */
-	if (par->fb_ready && par->update)
-		synthvid_update(info, x1, y1, x2, y2);
-}
-
-/*
- * Control the on-demand refresh frequency. It schedules a delayed
- * screen update if it has not yet.
- */
-static void hvfb_ondemand_refresh_throttle(struct hvfb_par *par,
-					   int x1, int y1, int w, int h)
-{
-	unsigned long flags;
-	int x2 = x1 + w;
-	int y2 = y1 + h;
-
-	spin_lock_irqsave(&par->delayed_refresh_lock, flags);
-
-	/* Merge dirty rectangle */
-	par->x1 = min_t(int, par->x1, x1);
-	par->y1 = min_t(int, par->y1, y1);
-	par->x2 = max_t(int, par->x2, x2);
-	par->y2 = max_t(int, par->y2, y2);
-
-	/* Schedule a delayed screen update if not yet */
-	if (par->delayed_refresh == false) {
-		schedule_delayed_work(&par->dwork,
-				      HVFB_ONDEMAND_THROTTLE);
-		par->delayed_refresh = true;
-	}
-
-	spin_unlock_irqrestore(&par->delayed_refresh_lock, flags);
-}
-
-static int hvfb_on_panic(struct notifier_block *nb,
-			 unsigned long e, void *p)
-{
-	struct hv_device *hdev;
-	struct hvfb_par *par;
-	struct fb_info *info;
-
-	par = container_of(nb, struct hvfb_par, hvfb_panic_nb);
-	info = par->info;
-	hdev = device_to_hv_device(info->device);
-
-	if (hv_ringbuffer_spinlock_busy(hdev->channel))
-		return NOTIFY_DONE;
-
-	par->synchronous_fb = true;
-	if (par->need_docopy)
-		hvfb_docopy(par, 0, dio_fb_size);
-	synthvid_update(info, 0, 0, INT_MAX, INT_MAX);
-
-	return NOTIFY_DONE;
-}
-
-/* Framebuffer operation handlers */
-
-static int hvfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
-{
-	if (var->xres < HVFB_WIDTH_MIN || var->yres < HVFB_HEIGHT_MIN ||
-	    var->xres > screen_width || var->yres >  screen_height ||
-	    var->bits_per_pixel != screen_depth)
-		return -EINVAL;
-
-	var->xres_virtual = var->xres;
-	var->yres_virtual = var->yres;
-
-	return 0;
-}
-
-static int hvfb_set_par(struct fb_info *info)
-{
-	struct hv_device *hdev = device_to_hv_device(info->device);
-
-	return synthvid_send_situ(hdev);
-}
-
-
-static inline u32 chan_to_field(u32 chan, struct fb_bitfield *bf)
-{
-	return ((chan & 0xffff) >> (16 - bf->length)) << bf->offset;
-}
-
-static int hvfb_setcolreg(unsigned regno, unsigned red, unsigned green,
-			  unsigned blue, unsigned transp, struct fb_info *info)
-{
-	u32 *pal = info->pseudo_palette;
-
-	if (regno > 15)
-		return -EINVAL;
-
-	pal[regno] = chan_to_field(red, &info->var.red)
-		| chan_to_field(green, &info->var.green)
-		| chan_to_field(blue, &info->var.blue)
-		| chan_to_field(transp, &info->var.transp);
-
-	return 0;
-}
-
-static int hvfb_blank(int blank, struct fb_info *info)
-{
-	return 1;	/* get fb_blank to set the colormap to all black */
-}
-
-static void hvfb_ops_damage_range(struct fb_info *info, off_t off, size_t len)
-{
-	/* TODO: implement damage handling */
-}
-
-static void hvfb_ops_damage_area(struct fb_info *info, u32 x, u32 y, u32 width, u32 height)
-{
-	struct hvfb_par *par = info->par;
-
-	if (par->synchronous_fb)
-		synthvid_update(info, 0, 0, INT_MAX, INT_MAX);
-	else
-		hvfb_ondemand_refresh_throttle(par, x, y, width, height);
-}
-
-/*
- * fb_ops.fb_destroy is called by the last put_fb_info() call at the end
- * of unregister_framebuffer() or fb_release(). Do any cleanup related to
- * framebuffer here.
- */
-static void hvfb_destroy(struct fb_info *info)
-{
-	hvfb_putmem(info);
-	framebuffer_release(info);
-}
-
-/*
- * TODO: GEN1 codepaths allocate from system or DMA-able memory. Fix the
- *       driver to use the _SYSMEM_ or _DMAMEM_ helpers in these cases.
- */
-FB_GEN_DEFAULT_DEFERRED_IOMEM_OPS(hvfb_ops,
-				  hvfb_ops_damage_range,
-				  hvfb_ops_damage_area)
-
-static const struct fb_ops hvfb_ops = {
-	.owner = THIS_MODULE,
-	FB_DEFAULT_DEFERRED_OPS(hvfb_ops),
-	.fb_check_var = hvfb_check_var,
-	.fb_set_par = hvfb_set_par,
-	.fb_setcolreg = hvfb_setcolreg,
-	.fb_blank = hvfb_blank,
-	.fb_destroy	= hvfb_destroy,
-};
-
-/* Get options from kernel paramenter "video=" */
-static void hvfb_get_option(struct fb_info *info)
-{
-	struct hvfb_par *par = info->par;
-	char *opt = NULL, *p;
-	uint x = 0, y = 0;
-
-	if (fb_get_options(KBUILD_MODNAME, &opt) || !opt || !*opt)
-		return;
-
-	p = strsep(&opt, "x");
-	if (!*p || kstrtouint(p, 0, &x) ||
-	    !opt || !*opt || kstrtouint(opt, 0, &y)) {
-		pr_err("Screen option is invalid: skipped\n");
-		return;
-	}
-
-	if (x < HVFB_WIDTH_MIN || y < HVFB_HEIGHT_MIN ||
-	    (synthvid_ver_ge(par->synthvid_version, SYNTHVID_VERSION_WIN10) &&
-	    (x * y * screen_depth / 8 > screen_fb_size)) ||
-	    (par->synthvid_version == SYNTHVID_VERSION_WIN8 &&
-	     x * y * screen_depth / 8 > SYNTHVID_FB_SIZE_WIN8)) {
-		pr_err("Screen resolution option is out of range: skipped\n");
-		return;
-	}
-
-	screen_width = x;
-	screen_height = y;
-	return;
-}
-
-/*
- * Allocate enough contiguous physical memory.
- * Return physical address if succeeded or -1 if failed.
- */
-static phys_addr_t hvfb_get_phymem(struct hv_device *hdev,
-				   unsigned int request_size)
-{
-	struct page *page = NULL;
-	dma_addr_t dma_handle;
-	void *vmem;
-	phys_addr_t paddr = 0;
-	unsigned int order = get_order(request_size);
-
-	if (request_size == 0)
-		return -1;
-
-	if (order <= MAX_PAGE_ORDER) {
-		/* Call alloc_pages if the size is less than 2^MAX_PAGE_ORDER */
-		page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
-		if (!page)
-			return -1;
-
-		paddr = (page_to_pfn(page) << PAGE_SHIFT);
-	} else {
-		/* Allocate from CMA */
-		hdev->device.coherent_dma_mask = DMA_BIT_MASK(64);
-
-		vmem = dma_alloc_coherent(&hdev->device,
-					  round_up(request_size, PAGE_SIZE),
-					  &dma_handle,
-					  GFP_KERNEL | __GFP_NOWARN);
-
-		if (!vmem)
-			return -1;
-
-		paddr = virt_to_phys(vmem);
-	}
-
-	return paddr;
-}
-
-/* Release contiguous physical memory */
-static void hvfb_release_phymem(struct device *device,
-				phys_addr_t paddr, unsigned int size)
-{
-	unsigned int order = get_order(size);
-
-	if (order <= MAX_PAGE_ORDER)
-		__free_pages(pfn_to_page(paddr >> PAGE_SHIFT), order);
-	else
-		dma_free_coherent(device,
-				  round_up(size, PAGE_SIZE),
-				  phys_to_virt(paddr),
-				  paddr);
-}
-
-
-/* Get framebuffer memory from Hyper-V video pci space */
-static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
-{
-	struct hvfb_par *par = info->par;
-	struct pci_dev *pdev  = NULL;
-	void __iomem *fb_virt;
-	int gen2vm = efi_enabled(EFI_BOOT);
-	resource_size_t base = 0;
-	resource_size_t size = 0;
-	phys_addr_t paddr;
-	int ret;
-
-	if (!gen2vm) {
-		pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT,
-			PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
-		if (!pdev) {
-			pr_err("Unable to find PCI Hyper-V video\n");
-			return -ENODEV;
-		}
-
-		base = pci_resource_start(pdev, 0);
-		size = pci_resource_len(pdev, 0);
-		aperture_remove_conflicting_devices(base, size, KBUILD_MODNAME);
-
-		/*
-		 * For Gen 1 VM, we can directly use the contiguous memory
-		 * from VM. If we succeed, deferred IO happens directly
-		 * on this allocated framebuffer memory, avoiding extra
-		 * memory copy.
-		 */
-		paddr = hvfb_get_phymem(hdev, screen_fb_size);
-		if (paddr != (phys_addr_t) -1) {
-			par->mmio_pp = paddr;
-			par->mmio_vp = par->dio_vp = __va(paddr);
-
-			info->fix.smem_start = paddr;
-			info->fix.smem_len = screen_fb_size;
-			info->screen_base = par->mmio_vp;
-			info->screen_size = screen_fb_size;
-
-			par->need_docopy = false;
-			goto getmem_done;
-		}
-		pr_info("Unable to allocate enough contiguous physical memory on Gen 1 VM. Using MMIO instead.\n");
-	} else {
-		aperture_remove_all_conflicting_devices(KBUILD_MODNAME);
-	}
-
-	/*
-	 * Cannot use contiguous physical memory, so allocate MMIO space for
-	 * the framebuffer. At this point in the function, conflicting devices
-	 * that might have claimed the framebuffer MMIO space based on
-	 * screen_info.lfb_base must have already been removed so that
-	 * vmbus_allocate_mmio() does not allocate different MMIO space. If the
-	 * kdump image were to be loaded using kexec_file_load(), the
-	 * framebuffer location in the kdump image would be set from
-	 * screen_info.lfb_base at the time that kdump is enabled. If the
-	 * framebuffer has moved elsewhere, this could be the wrong location,
-	 * causing kdump to hang when efifb (for example) loads.
-	 */
-	dio_fb_size =
-		screen_width * screen_height * screen_depth / 8;
-
-	ret = vmbus_allocate_mmio(&par->mem, hdev, 0, -1,
-				  screen_fb_size, 0x100000, true);
-	if (ret != 0) {
-		pr_err("Unable to allocate framebuffer memory\n");
-		goto err1;
-	}
-
-	/*
-	 * Map the VRAM cacheable for performance. This is also required for
-	 * VM Connect to display properly for ARM64 Linux VM, as the host also
-	 * maps the VRAM cacheable.
-	 */
-	fb_virt = ioremap_cache(par->mem->start, screen_fb_size);
-	if (!fb_virt)
-		goto err2;
-
-	/* Allocate memory for deferred IO */
-	par->dio_vp = vzalloc(round_up(dio_fb_size, PAGE_SIZE));
-	if (par->dio_vp == NULL)
-		goto err3;
-
-	/* Physical address of FB device */
-	par->mmio_pp = par->mem->start;
-	/* Virtual address of FB device */
-	par->mmio_vp = (unsigned char *) fb_virt;
-
-	info->fix.smem_start = par->mem->start;
-	info->fix.smem_len = dio_fb_size;
-	info->screen_base = par->dio_vp;
-	info->screen_size = dio_fb_size;
-
-getmem_done:
-	if (!gen2vm)
-		pci_dev_put(pdev);
-
-	return 0;
-
-err3:
-	iounmap(fb_virt);
-err2:
-	vmbus_free_mmio(par->mem->start, screen_fb_size);
-	par->mem = NULL;
-err1:
-	if (!gen2vm)
-		pci_dev_put(pdev);
-
-	return -ENOMEM;
-}
-
-/* Release the framebuffer */
-static void hvfb_putmem(struct fb_info *info)
-{
-	struct hvfb_par *par = info->par;
-
-	if (par->need_docopy) {
-		vfree(par->dio_vp);
-		iounmap(par->mmio_vp);
-		vmbus_free_mmio(par->mem->start, screen_fb_size);
-	} else {
-		hvfb_release_phymem(info->device, info->fix.smem_start,
-				    screen_fb_size);
-	}
-
-	par->mem = NULL;
-}
-
-
-static int hvfb_probe(struct hv_device *hdev,
-		      const struct hv_vmbus_device_id *dev_id)
-{
-	struct fb_info *info;
-	struct hvfb_par *par;
-	int ret;
-
-	info = framebuffer_alloc(sizeof(struct hvfb_par), &hdev->device);
-	if (!info)
-		return -ENOMEM;
-
-	par = info->par;
-	par->info = info;
-	par->fb_ready = false;
-	par->need_docopy = true;
-	init_completion(&par->wait);
-	INIT_DELAYED_WORK(&par->dwork, hvfb_update_work);
-
-	par->delayed_refresh = false;
-	spin_lock_init(&par->delayed_refresh_lock);
-	par->x1 = par->y1 = INT_MAX;
-	par->x2 = par->y2 = 0;
-
-	/* Connect to VSP */
-	hv_set_drvdata(hdev, info);
-	ret = synthvid_connect_vsp(hdev);
-	if (ret) {
-		pr_err("Unable to connect to VSP\n");
-		goto error1;
-	}
-
-	hvfb_get_option(info);
-	pr_info("Screen resolution: %dx%d, Color depth: %d, Frame buffer size: %d\n",
-		screen_width, screen_height, screen_depth, screen_fb_size);
-
-	ret = hvfb_getmem(hdev, info);
-	if (ret) {
-		pr_err("No memory for framebuffer\n");
-		goto error2;
-	}
-
-	/* Set up fb_info */
-	info->var.xres_virtual = info->var.xres = screen_width;
-	info->var.yres_virtual = info->var.yres = screen_height;
-	info->var.bits_per_pixel = screen_depth;
-
-	if (info->var.bits_per_pixel == 16) {
-		info->var.red = (struct fb_bitfield){11, 5, 0};
-		info->var.green = (struct fb_bitfield){5, 6, 0};
-		info->var.blue = (struct fb_bitfield){0, 5, 0};
-		info->var.transp = (struct fb_bitfield){0, 0, 0};
-	} else {
-		info->var.red = (struct fb_bitfield){16, 8, 0};
-		info->var.green = (struct fb_bitfield){8, 8, 0};
-		info->var.blue = (struct fb_bitfield){0, 8, 0};
-		info->var.transp = (struct fb_bitfield){24, 8, 0};
-	}
-
-	info->var.activate = FB_ACTIVATE_NOW;
-	info->var.height = -1;
-	info->var.width = -1;
-	info->var.vmode = FB_VMODE_NONINTERLACED;
-
-	strcpy(info->fix.id, KBUILD_MODNAME);
-	info->fix.type = FB_TYPE_PACKED_PIXELS;
-	info->fix.visual = FB_VISUAL_TRUECOLOR;
-	info->fix.line_length = screen_width * screen_depth / 8;
-	info->fix.accel = FB_ACCEL_NONE;
-
-	info->fbops = &hvfb_ops;
-	info->pseudo_palette = par->pseudo_palette;
-
-	/* Initialize deferred IO */
-	info->fbdefio = &synthvid_defio;
-	fb_deferred_io_init(info);
-
-	/* Send config to host */
-	ret = synthvid_send_config(hdev);
-	if (ret)
-		goto error;
-
-	ret = devm_register_framebuffer(&hdev->device, info);
-	if (ret) {
-		pr_err("Unable to register framebuffer\n");
-		goto error;
-	}
-
-	par->fb_ready = true;
-
-	par->synchronous_fb = false;
-
-	/*
-	 * We need to be sure this panic notifier runs _before_ the
-	 * vmbus disconnect, so order it by priority. It must execute
-	 * before the function hv_panic_vmbus_unload() [drivers/hv/vmbus_drv.c],
-	 * which is almost at the end of list, with priority = INT_MIN + 1.
-	 */
-	par->hvfb_panic_nb.notifier_call = hvfb_on_panic;
-	par->hvfb_panic_nb.priority = INT_MIN + 10;
-	atomic_notifier_chain_register(&panic_notifier_list,
-				       &par->hvfb_panic_nb);
-
-	return 0;
-
-error:
-	fb_deferred_io_cleanup(info);
-	hvfb_putmem(info);
-error2:
-	vmbus_close(hdev->channel);
-error1:
-	cancel_delayed_work_sync(&par->dwork);
-	hv_set_drvdata(hdev, NULL);
-	framebuffer_release(info);
-	return ret;
-}
-
-static void hvfb_remove(struct hv_device *hdev)
-{
-	struct fb_info *info = hv_get_drvdata(hdev);
-	struct hvfb_par *par = info->par;
-
-	atomic_notifier_chain_unregister(&panic_notifier_list,
-					 &par->hvfb_panic_nb);
-
-	par->update = false;
-	par->fb_ready = false;
-
-	fb_deferred_io_cleanup(info);
-
-	cancel_delayed_work_sync(&par->dwork);
-
-	vmbus_close(hdev->channel);
-	hv_set_drvdata(hdev, NULL);
-}
-
-static int hvfb_suspend(struct hv_device *hdev)
-{
-	struct fb_info *info = hv_get_drvdata(hdev);
-	struct hvfb_par *par = info->par;
-
-	console_lock();
-
-	/* 1 means do suspend */
-	fb_set_suspend(info, 1);
-
-	cancel_delayed_work_sync(&par->dwork);
-	cancel_delayed_work_sync(&info->deferred_work);
-
-	par->update_saved = par->update;
-	par->update = false;
-	par->fb_ready = false;
-
-	vmbus_close(hdev->channel);
-
-	console_unlock();
-
-	return 0;
-}
-
-static int hvfb_resume(struct hv_device *hdev)
-{
-	struct fb_info *info = hv_get_drvdata(hdev);
-	struct hvfb_par *par = info->par;
-	int ret;
-
-	console_lock();
-
-	ret = synthvid_connect_vsp(hdev);
-	if (ret != 0)
-		goto out;
-
-	ret = synthvid_send_config(hdev);
-	if (ret != 0) {
-		vmbus_close(hdev->channel);
-		goto out;
-	}
-
-	par->fb_ready = true;
-	par->update = par->update_saved;
-
-	schedule_delayed_work(&info->deferred_work, info->fbdefio->delay);
-	schedule_delayed_work(&par->dwork, HVFB_UPDATE_DELAY);
-
-	/* 0 means do resume */
-	fb_set_suspend(info, 0);
-
-out:
-	console_unlock();
-
-	return ret;
-}
-
-
-static const struct pci_device_id pci_stub_id_table[] = {
-	{
-		.vendor      = PCI_VENDOR_ID_MICROSOFT,
-		.device      = PCI_DEVICE_ID_HYPERV_VIDEO,
-	},
-	{ /* end of list */ }
-};
-
-static const struct hv_vmbus_device_id id_table[] = {
-	/* Synthetic Video Device GUID */
-	{HV_SYNTHVID_GUID},
-	{}
-};
-
-MODULE_DEVICE_TABLE(pci, pci_stub_id_table);
-MODULE_DEVICE_TABLE(vmbus, id_table);
-
-static struct hv_driver hvfb_drv = {
-	.name = KBUILD_MODNAME,
-	.id_table = id_table,
-	.probe = hvfb_probe,
-	.remove = hvfb_remove,
-	.suspend = hvfb_suspend,
-	.resume = hvfb_resume,
-	.driver = {
-		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
-	},
-};
-
-static int hvfb_pci_stub_probe(struct pci_dev *pdev,
-			       const struct pci_device_id *ent)
-{
-	return 0;
-}
-
-static void hvfb_pci_stub_remove(struct pci_dev *pdev)
-{
-}
-
-static struct pci_driver hvfb_pci_stub_driver = {
-	.name =		KBUILD_MODNAME,
-	.id_table =	pci_stub_id_table,
-	.probe =	hvfb_pci_stub_probe,
-	.remove =	hvfb_pci_stub_remove,
-	.driver = {
-		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
-	}
-};
-
-static int __init hvfb_drv_init(void)
-{
-	int ret;
-
-	if (fb_modesetting_disabled("hyper_fb"))
-		return -ENODEV;
-
-	ret = vmbus_driver_register(&hvfb_drv);
-	if (ret != 0)
-		return ret;
-
-	ret = pci_register_driver(&hvfb_pci_stub_driver);
-	if (ret != 0) {
-		vmbus_driver_unregister(&hvfb_drv);
-		return ret;
-	}
-
-	return 0;
-}
-
-static void __exit hvfb_drv_exit(void)
-{
-	pci_unregister_driver(&hvfb_pci_stub_driver);
-	vmbus_driver_unregister(&hvfb_drv);
-}
-
-module_init(hvfb_drv_init);
-module_exit(hvfb_drv_exit);
-
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("Microsoft Hyper-V Synthetic Video Frame Buffer Driver");
-- 
2.49.0

Re: [RFC 1/3] fbdev: hyperv_fb: Remove hyperv_fb driver

[Thomas Zimmermann]

Hi

Am 09.09.25 um 18:58 schrieb Prasanna Kumar T S M:
> The Hyper-V DRM driver is available since kernel version 5.14 and
> provides full KMS support along with fbdev emulation via the DRM fbdev
> helpers. This makes the hyperv_fb driver redundant, remove it.

I'm all for removing obsolete drivers. But hyperv_drm likely first needs 
to merge the patch at 
https://lore.kernel.org/dri-devel/20250904145806.430568-5-tzimmermann@suse.de/ 
It's been tested and works well. If maintainers from Microsoft have a 
look at the patch first, we could possibly land it fairly soon.

Best regards
Thomas

>
> Signed-off-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com>
> ---
>   MAINTAINERS                     |    1 -
>   drivers/video/fbdev/Kconfig     |    8 -
>   drivers/video/fbdev/Makefile    |    1 -
>   drivers/video/fbdev/hyperv_fb.c | 1386 -------------------------------
>   4 files changed, 1396 deletions(-)
>   delete mode 100644 drivers/video/fbdev/hyperv_fb.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e94d68c980c5..9d0f0e929356 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11416,7 +11416,6 @@ F:	drivers/pci/controller/pci-hyperv-intf.c
>   F:	drivers/pci/controller/pci-hyperv.c
>   F:	drivers/scsi/storvsc_drv.c
>   F:	drivers/uio/uio_hv_generic.c
> -F:	drivers/video/fbdev/hyperv_fb.c
>   F:	include/asm-generic/mshyperv.h
>   F:	include/clocksource/hyperv_timer.h
>   F:	include/hyperv/hvgdk.h
> diff --git a/drivers/video/fbdev/Kconfig b/drivers/video/fbdev/Kconfig
> index c21484d15f0c..bb8ac759f6aa 100644
> --- a/drivers/video/fbdev/Kconfig
> +++ b/drivers/video/fbdev/Kconfig
> @@ -1772,14 +1772,6 @@ config FB_BROADSHEET
>   	  and could also have been called by other names when coupled with
>   	  a bridge adapter.
>   
> -config FB_HYPERV
> -	tristate "Microsoft Hyper-V Synthetic Video support"
> -	depends on FB && HYPERV
> -	select DMA_CMA if HAVE_DMA_CONTIGUOUS && CMA
> -	select FB_IOMEM_HELPERS_DEFERRED
> -	help
> -	  This framebuffer driver supports Microsoft Hyper-V Synthetic Video.
> -
>   config FB_SIMPLE
>   	tristate "Simple framebuffer support"
>   	depends on FB
> diff --git a/drivers/video/fbdev/Makefile b/drivers/video/fbdev/Makefile
> index b3d12f977c06..36a18d958ba0 100644
> --- a/drivers/video/fbdev/Makefile
> +++ b/drivers/video/fbdev/Makefile
> @@ -111,7 +111,6 @@ obj-y                             += omap2/
>   obj-$(CONFIG_XEN_FBDEV_FRONTEND)  += xen-fbfront.o
>   obj-$(CONFIG_FB_CARMINE)          += carminefb.o
>   obj-$(CONFIG_FB_MB862XX)	  += mb862xx/
> -obj-$(CONFIG_FB_HYPERV)		  += hyperv_fb.o
>   obj-$(CONFIG_FB_OPENCORES)	  += ocfb.o
>   obj-$(CONFIG_FB_SM712)		  += sm712fb.o
>   
> diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
> deleted file mode 100644
> index 75338ffc703f..000000000000
> --- a/drivers/video/fbdev/hyperv_fb.c
> +++ /dev/null
> @@ -1,1386 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0-only
> -/*
> - * Copyright (c) 2012, Microsoft Corporation.
> - *
> - * Author:
> - *   Haiyang Zhang <haiyangz@microsoft.com>
> - */
> -
> -/*
> - * Hyper-V Synthetic Video Frame Buffer Driver
> - *
> - * This is the driver for the Hyper-V Synthetic Video, which supports
> - * screen resolution up to Full HD 1920x1080 with 32 bit color on Windows
> - * Server 2012, and 1600x1200 with 16 bit color on Windows Server 2008 R2
> - * or earlier.
> - *
> - * It also solves the double mouse cursor issue of the emulated video mode.
> - *
> - * The default screen resolution is 1152x864, which may be changed by a
> - * kernel parameter:
> - *     video=hyperv_fb:<width>x<height>
> - *     For example: video=hyperv_fb:1280x1024
> - *
> - * Portrait orientation is also supported:
> - *     For example: video=hyperv_fb:864x1152
> - *
> - * When a Windows 10 RS5+ host is used, the virtual machine screen
> - * resolution is obtained from the host. The "video=hyperv_fb" option is
> - * not needed, but still can be used to overwrite what the host specifies.
> - * The VM resolution on the host could be set by executing the powershell
> - * "set-vmvideo" command. For example
> - *     set-vmvideo -vmname name -horizontalresolution:1920 \
> - * -verticalresolution:1200 -resolutiontype single
> - *
> - * Gen 1 VMs also support direct using VM's physical memory for framebuffer.
> - * It could improve the efficiency and performance for framebuffer and VM.
> - * This requires to allocate contiguous physical memory from Linux kernel's
> - * CMA memory allocator. To enable this, supply a kernel parameter to give
> - * enough memory space to CMA allocator for framebuffer. For example:
> - *    cma=130m
> - * This gives 130MB memory to CMA allocator that can be allocated to
> - * framebuffer. For reference, 8K resolution (7680x4320) takes about
> - * 127MB memory.
> - */
> -
> -#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> -
> -#include <linux/aperture.h>
> -#include <linux/module.h>
> -#include <linux/kernel.h>
> -#include <linux/vmalloc.h>
> -#include <linux/init.h>
> -#include <linux/completion.h>
> -#include <linux/fb.h>
> -#include <linux/pci.h>
> -#include <linux/panic_notifier.h>
> -#include <linux/efi.h>
> -#include <linux/console.h>
> -
> -#include <linux/hyperv.h>
> -
> -/* Hyper-V Synthetic Video Protocol definitions and structures */
> -#define MAX_VMBUS_PKT_SIZE 0x4000
> -
> -#define SYNTHVID_VERSION(major, minor) ((minor) << 16 | (major))
> -/* Support for VERSION_WIN7 is removed. #define is retained for reference. */
> -#define SYNTHVID_VERSION_WIN7 SYNTHVID_VERSION(3, 0)
> -#define SYNTHVID_VERSION_WIN8 SYNTHVID_VERSION(3, 2)
> -#define SYNTHVID_VERSION_WIN10 SYNTHVID_VERSION(3, 5)
> -
> -#define SYNTHVID_VER_GET_MAJOR(ver) (ver & 0x0000ffff)
> -#define SYNTHVID_VER_GET_MINOR(ver) ((ver & 0xffff0000) >> 16)
> -
> -#define SYNTHVID_DEPTH_WIN8 32
> -#define SYNTHVID_FB_SIZE_WIN8 (8 * 1024 * 1024)
> -
> -enum pipe_msg_type {
> -	PIPE_MSG_INVALID,
> -	PIPE_MSG_DATA,
> -	PIPE_MSG_MAX
> -};
> -
> -struct pipe_msg_hdr {
> -	u32 type;
> -	u32 size; /* size of message after this field */
> -} __packed;
> -
> -
> -enum synthvid_msg_type {
> -	SYNTHVID_ERROR			= 0,
> -	SYNTHVID_VERSION_REQUEST	= 1,
> -	SYNTHVID_VERSION_RESPONSE	= 2,
> -	SYNTHVID_VRAM_LOCATION		= 3,
> -	SYNTHVID_VRAM_LOCATION_ACK	= 4,
> -	SYNTHVID_SITUATION_UPDATE	= 5,
> -	SYNTHVID_SITUATION_UPDATE_ACK	= 6,
> -	SYNTHVID_POINTER_POSITION	= 7,
> -	SYNTHVID_POINTER_SHAPE		= 8,
> -	SYNTHVID_FEATURE_CHANGE		= 9,
> -	SYNTHVID_DIRT			= 10,
> -	SYNTHVID_RESOLUTION_REQUEST	= 13,
> -	SYNTHVID_RESOLUTION_RESPONSE	= 14,
> -
> -	SYNTHVID_MAX			= 15
> -};
> -
> -#define		SYNTHVID_EDID_BLOCK_SIZE	128
> -#define		SYNTHVID_MAX_RESOLUTION_COUNT	64
> -
> -struct hvd_screen_info {
> -	u16 width;
> -	u16 height;
> -} __packed;
> -
> -struct synthvid_msg_hdr {
> -	u32 type;
> -	u32 size;  /* size of this header + payload after this field*/
> -} __packed;
> -
> -struct synthvid_version_req {
> -	u32 version;
> -} __packed;
> -
> -struct synthvid_version_resp {
> -	u32 version;
> -	u8 is_accepted;
> -	u8 max_video_outputs;
> -} __packed;
> -
> -struct synthvid_supported_resolution_req {
> -	u8 maximum_resolution_count;
> -} __packed;
> -
> -struct synthvid_supported_resolution_resp {
> -	u8 edid_block[SYNTHVID_EDID_BLOCK_SIZE];
> -	u8 resolution_count;
> -	u8 default_resolution_index;
> -	u8 is_standard;
> -	struct hvd_screen_info
> -		supported_resolution[SYNTHVID_MAX_RESOLUTION_COUNT];
> -} __packed;
> -
> -struct synthvid_vram_location {
> -	u64 user_ctx;
> -	u8 is_vram_gpa_specified;
> -	u64 vram_gpa;
> -} __packed;
> -
> -struct synthvid_vram_location_ack {
> -	u64 user_ctx;
> -} __packed;
> -
> -struct video_output_situation {
> -	u8 active;
> -	u32 vram_offset;
> -	u8 depth_bits;
> -	u32 width_pixels;
> -	u32 height_pixels;
> -	u32 pitch_bytes;
> -} __packed;
> -
> -struct synthvid_situation_update {
> -	u64 user_ctx;
> -	u8 video_output_count;
> -	struct video_output_situation video_output[1];
> -} __packed;
> -
> -struct synthvid_situation_update_ack {
> -	u64 user_ctx;
> -} __packed;
> -
> -struct synthvid_pointer_position {
> -	u8 is_visible;
> -	u8 video_output;
> -	s32 image_x;
> -	s32 image_y;
> -} __packed;
> -
> -
> -#define CURSOR_MAX_X 96
> -#define CURSOR_MAX_Y 96
> -#define CURSOR_ARGB_PIXEL_SIZE 4
> -#define CURSOR_MAX_SIZE (CURSOR_MAX_X * CURSOR_MAX_Y * CURSOR_ARGB_PIXEL_SIZE)
> -#define CURSOR_COMPLETE (-1)
> -
> -struct synthvid_pointer_shape {
> -	u8 part_idx;
> -	u8 is_argb;
> -	u32 width; /* CURSOR_MAX_X at most */
> -	u32 height; /* CURSOR_MAX_Y at most */
> -	u32 hot_x; /* hotspot relative to upper-left of pointer image */
> -	u32 hot_y;
> -	u8 data[4];
> -} __packed;
> -
> -struct synthvid_feature_change {
> -	u8 is_dirt_needed;
> -	u8 is_ptr_pos_needed;
> -	u8 is_ptr_shape_needed;
> -	u8 is_situ_needed;
> -} __packed;
> -
> -struct rect {
> -	s32 x1, y1; /* top left corner */
> -	s32 x2, y2; /* bottom right corner, exclusive */
> -} __packed;
> -
> -struct synthvid_dirt {
> -	u8 video_output;
> -	u8 dirt_count;
> -	struct rect rect[1];
> -} __packed;
> -
> -struct synthvid_msg {
> -	struct pipe_msg_hdr pipe_hdr;
> -	struct synthvid_msg_hdr vid_hdr;
> -	union {
> -		struct synthvid_version_req ver_req;
> -		struct synthvid_version_resp ver_resp;
> -		struct synthvid_vram_location vram;
> -		struct synthvid_vram_location_ack vram_ack;
> -		struct synthvid_situation_update situ;
> -		struct synthvid_situation_update_ack situ_ack;
> -		struct synthvid_pointer_position ptr_pos;
> -		struct synthvid_pointer_shape ptr_shape;
> -		struct synthvid_feature_change feature_chg;
> -		struct synthvid_dirt dirt;
> -		struct synthvid_supported_resolution_req resolution_req;
> -		struct synthvid_supported_resolution_resp resolution_resp;
> -	};
> -} __packed;
> -
> -
> -/* FB driver definitions and structures */
> -#define HVFB_WIDTH 1152 /* default screen width */
> -#define HVFB_HEIGHT 864 /* default screen height */
> -#define HVFB_WIDTH_MIN 640
> -#define HVFB_HEIGHT_MIN 480
> -
> -#define RING_BUFSIZE (256 * 1024)
> -#define VSP_TIMEOUT (10 * HZ)
> -#define HVFB_UPDATE_DELAY (HZ / 20)
> -#define HVFB_ONDEMAND_THROTTLE (HZ / 20)
> -
> -struct hvfb_par {
> -	struct fb_info *info;
> -	struct resource *mem;
> -	bool fb_ready; /* fb device is ready */
> -	struct completion wait;
> -	u32 synthvid_version;
> -
> -	struct delayed_work dwork;
> -	bool update;
> -	bool update_saved; /* The value of 'update' before hibernation */
> -
> -	u32 pseudo_palette[16];
> -	u8 init_buf[MAX_VMBUS_PKT_SIZE];
> -	u8 recv_buf[MAX_VMBUS_PKT_SIZE];
> -
> -	/* If true, the VSC notifies the VSP on every framebuffer change */
> -	bool synchronous_fb;
> -
> -	/* If true, need to copy from deferred IO mem to framebuffer mem */
> -	bool need_docopy;
> -
> -	struct notifier_block hvfb_panic_nb;
> -
> -	/* Memory for deferred IO and frame buffer itself */
> -	unsigned char *dio_vp;
> -	unsigned char *mmio_vp;
> -	phys_addr_t mmio_pp;
> -
> -	/* Dirty rectangle, protected by delayed_refresh_lock */
> -	int x1, y1, x2, y2;
> -	bool delayed_refresh;
> -	spinlock_t delayed_refresh_lock;
> -};
> -
> -static uint screen_width = HVFB_WIDTH;
> -static uint screen_height = HVFB_HEIGHT;
> -static uint screen_depth;
> -static uint screen_fb_size;
> -static uint dio_fb_size; /* FB size for deferred IO */
> -
> -static void hvfb_putmem(struct fb_info *info);
> -
> -/* Send message to Hyper-V host */
> -static inline int synthvid_send(struct hv_device *hdev,
> -				struct synthvid_msg *msg)
> -{
> -	static atomic64_t request_id = ATOMIC64_INIT(0);
> -	int ret;
> -
> -	msg->pipe_hdr.type = PIPE_MSG_DATA;
> -	msg->pipe_hdr.size = msg->vid_hdr.size;
> -
> -	ret = vmbus_sendpacket(hdev->channel, msg,
> -			       msg->vid_hdr.size + sizeof(struct pipe_msg_hdr),
> -			       atomic64_inc_return(&request_id),
> -			       VM_PKT_DATA_INBAND, 0);
> -
> -	if (ret)
> -		pr_err_ratelimited("Unable to send packet via vmbus; error %d\n", ret);
> -
> -	return ret;
> -}
> -
> -
> -/* Send screen resolution info to host */
> -static int synthvid_send_situ(struct hv_device *hdev)
> -{
> -	struct fb_info *info = hv_get_drvdata(hdev);
> -	struct synthvid_msg msg;
> -
> -	if (!info)
> -		return -ENODEV;
> -
> -	memset(&msg, 0, sizeof(struct synthvid_msg));
> -
> -	msg.vid_hdr.type = SYNTHVID_SITUATION_UPDATE;
> -	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
> -		sizeof(struct synthvid_situation_update);
> -	msg.situ.user_ctx = 0;
> -	msg.situ.video_output_count = 1;
> -	msg.situ.video_output[0].active = 1;
> -	msg.situ.video_output[0].vram_offset = 0;
> -	msg.situ.video_output[0].depth_bits = info->var.bits_per_pixel;
> -	msg.situ.video_output[0].width_pixels = info->var.xres;
> -	msg.situ.video_output[0].height_pixels = info->var.yres;
> -	msg.situ.video_output[0].pitch_bytes = info->fix.line_length;
> -
> -	synthvid_send(hdev, &msg);
> -
> -	return 0;
> -}
> -
> -/* Send mouse pointer info to host */
> -static int synthvid_send_ptr(struct hv_device *hdev)
> -{
> -	struct synthvid_msg msg;
> -
> -	memset(&msg, 0, sizeof(struct synthvid_msg));
> -	msg.vid_hdr.type = SYNTHVID_POINTER_POSITION;
> -	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
> -		sizeof(struct synthvid_pointer_position);
> -	msg.ptr_pos.is_visible = 1;
> -	msg.ptr_pos.video_output = 0;
> -	msg.ptr_pos.image_x = 0;
> -	msg.ptr_pos.image_y = 0;
> -	synthvid_send(hdev, &msg);
> -
> -	memset(&msg, 0, sizeof(struct synthvid_msg));
> -	msg.vid_hdr.type = SYNTHVID_POINTER_SHAPE;
> -	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
> -		sizeof(struct synthvid_pointer_shape);
> -	msg.ptr_shape.part_idx = CURSOR_COMPLETE;
> -	msg.ptr_shape.is_argb = 1;
> -	msg.ptr_shape.width = 1;
> -	msg.ptr_shape.height = 1;
> -	msg.ptr_shape.hot_x = 0;
> -	msg.ptr_shape.hot_y = 0;
> -	msg.ptr_shape.data[0] = 0;
> -	msg.ptr_shape.data[1] = 1;
> -	msg.ptr_shape.data[2] = 1;
> -	msg.ptr_shape.data[3] = 1;
> -	synthvid_send(hdev, &msg);
> -
> -	return 0;
> -}
> -
> -/* Send updated screen area (dirty rectangle) location to host */
> -static int
> -synthvid_update(struct fb_info *info, int x1, int y1, int x2, int y2)
> -{
> -	struct hv_device *hdev = device_to_hv_device(info->device);
> -	struct synthvid_msg msg;
> -
> -	memset(&msg, 0, sizeof(struct synthvid_msg));
> -	if (x2 == INT_MAX)
> -		x2 = info->var.xres;
> -	if (y2 == INT_MAX)
> -		y2 = info->var.yres;
> -
> -	msg.vid_hdr.type = SYNTHVID_DIRT;
> -	msg.vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
> -		sizeof(struct synthvid_dirt);
> -	msg.dirt.video_output = 0;
> -	msg.dirt.dirt_count = 1;
> -	msg.dirt.rect[0].x1 = (x1 > x2) ? 0 : x1;
> -	msg.dirt.rect[0].y1 = (y1 > y2) ? 0 : y1;
> -	msg.dirt.rect[0].x2 =
> -		(x2 < x1 || x2 > info->var.xres) ? info->var.xres : x2;
> -	msg.dirt.rect[0].y2 =
> -		(y2 < y1 || y2 > info->var.yres) ? info->var.yres : y2;
> -
> -	synthvid_send(hdev, &msg);
> -
> -	return 0;
> -}
> -
> -static void hvfb_docopy(struct hvfb_par *par,
> -			unsigned long offset,
> -			unsigned long size)
> -{
> -	if (!par || !par->mmio_vp || !par->dio_vp || !par->fb_ready ||
> -	    size == 0 || offset >= dio_fb_size)
> -		return;
> -
> -	if (offset + size > dio_fb_size)
> -		size = dio_fb_size - offset;
> -
> -	memcpy(par->mmio_vp + offset, par->dio_vp + offset, size);
> -}
> -
> -/* Deferred IO callback */
> -static void synthvid_deferred_io(struct fb_info *p, struct list_head *pagereflist)
> -{
> -	struct hvfb_par *par = p->par;
> -	struct fb_deferred_io_pageref *pageref;
> -	unsigned long start, end;
> -	int y1, y2, miny, maxy;
> -
> -	miny = INT_MAX;
> -	maxy = 0;
> -
> -	/*
> -	 * Merge dirty pages. It is possible that last page cross
> -	 * over the end of frame buffer row yres. This is taken care of
> -	 * in synthvid_update function by clamping the y2
> -	 * value to yres.
> -	 */
> -	list_for_each_entry(pageref, pagereflist, list) {
> -		start = pageref->offset;
> -		end = start + PAGE_SIZE - 1;
> -		y1 = start / p->fix.line_length;
> -		y2 = end / p->fix.line_length;
> -		miny = min_t(int, miny, y1);
> -		maxy = max_t(int, maxy, y2);
> -
> -		/* Copy from dio space to mmio address */
> -		if (par->fb_ready && par->need_docopy)
> -			hvfb_docopy(par, start, PAGE_SIZE);
> -	}
> -
> -	if (par->fb_ready && par->update)
> -		synthvid_update(p, 0, miny, p->var.xres, maxy + 1);
> -}
> -
> -static struct fb_deferred_io synthvid_defio = {
> -	.delay		= HZ / 20,
> -	.deferred_io	= synthvid_deferred_io,
> -};
> -
> -/*
> - * Actions on received messages from host:
> - * Complete the wait event.
> - * Or, reply with screen and cursor info.
> - */
> -static void synthvid_recv_sub(struct hv_device *hdev)
> -{
> -	struct fb_info *info = hv_get_drvdata(hdev);
> -	struct hvfb_par *par;
> -	struct synthvid_msg *msg;
> -
> -	if (!info)
> -		return;
> -
> -	par = info->par;
> -	msg = (struct synthvid_msg *)par->recv_buf;
> -
> -	/* Complete the wait event */
> -	if (msg->vid_hdr.type == SYNTHVID_VERSION_RESPONSE ||
> -	    msg->vid_hdr.type == SYNTHVID_RESOLUTION_RESPONSE ||
> -	    msg->vid_hdr.type == SYNTHVID_VRAM_LOCATION_ACK) {
> -		memcpy(par->init_buf, msg, MAX_VMBUS_PKT_SIZE);
> -		complete(&par->wait);
> -		return;
> -	}
> -
> -	/* Reply with screen and cursor info */
> -	if (msg->vid_hdr.type == SYNTHVID_FEATURE_CHANGE) {
> -		if (par->fb_ready) {
> -			synthvid_send_ptr(hdev);
> -			synthvid_send_situ(hdev);
> -		}
> -
> -		par->update = msg->feature_chg.is_dirt_needed;
> -		if (par->update)
> -			schedule_delayed_work(&par->dwork, HVFB_UPDATE_DELAY);
> -	}
> -}
> -
> -/* Receive callback for messages from the host */
> -static void synthvid_receive(void *ctx)
> -{
> -	struct hv_device *hdev = ctx;
> -	struct fb_info *info = hv_get_drvdata(hdev);
> -	struct hvfb_par *par;
> -	struct synthvid_msg *recv_buf;
> -	u32 bytes_recvd;
> -	u64 req_id;
> -	int ret;
> -
> -	if (!info)
> -		return;
> -
> -	par = info->par;
> -	recv_buf = (struct synthvid_msg *)par->recv_buf;
> -
> -	do {
> -		ret = vmbus_recvpacket(hdev->channel, recv_buf,
> -				       MAX_VMBUS_PKT_SIZE,
> -				       &bytes_recvd, &req_id);
> -		if (bytes_recvd > 0 &&
> -		    recv_buf->pipe_hdr.type == PIPE_MSG_DATA)
> -			synthvid_recv_sub(hdev);
> -	} while (bytes_recvd > 0 && ret == 0);
> -}
> -
> -/* Check if the ver1 version is equal or greater than ver2 */
> -static inline bool synthvid_ver_ge(u32 ver1, u32 ver2)
> -{
> -	if (SYNTHVID_VER_GET_MAJOR(ver1) > SYNTHVID_VER_GET_MAJOR(ver2) ||
> -	    (SYNTHVID_VER_GET_MAJOR(ver1) == SYNTHVID_VER_GET_MAJOR(ver2) &&
> -	     SYNTHVID_VER_GET_MINOR(ver1) >= SYNTHVID_VER_GET_MINOR(ver2)))
> -		return true;
> -
> -	return false;
> -}
> -
> -/* Check synthetic video protocol version with the host */
> -static int synthvid_negotiate_ver(struct hv_device *hdev, u32 ver)
> -{
> -	struct fb_info *info = hv_get_drvdata(hdev);
> -	struct hvfb_par *par = info->par;
> -	struct synthvid_msg *msg = (struct synthvid_msg *)par->init_buf;
> -	int ret = 0;
> -	unsigned long t;
> -
> -	memset(msg, 0, sizeof(struct synthvid_msg));
> -	msg->vid_hdr.type = SYNTHVID_VERSION_REQUEST;
> -	msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
> -		sizeof(struct synthvid_version_req);
> -	msg->ver_req.version = ver;
> -	synthvid_send(hdev, msg);
> -
> -	t = wait_for_completion_timeout(&par->wait, VSP_TIMEOUT);
> -	if (!t) {
> -		pr_err("Time out on waiting version response\n");
> -		ret = -ETIMEDOUT;
> -		goto out;
> -	}
> -	if (!msg->ver_resp.is_accepted) {
> -		ret = -ENODEV;
> -		goto out;
> -	}
> -
> -	par->synthvid_version = ver;
> -	pr_info("Synthvid Version major %d, minor %d\n",
> -		SYNTHVID_VER_GET_MAJOR(ver), SYNTHVID_VER_GET_MINOR(ver));
> -
> -out:
> -	return ret;
> -}
> -
> -/* Get current resolution from the host */
> -static int synthvid_get_supported_resolution(struct hv_device *hdev)
> -{
> -	struct fb_info *info = hv_get_drvdata(hdev);
> -	struct hvfb_par *par = info->par;
> -	struct synthvid_msg *msg = (struct synthvid_msg *)par->init_buf;
> -	int ret = 0;
> -	unsigned long t;
> -	u8 index;
> -
> -	memset(msg, 0, sizeof(struct synthvid_msg));
> -	msg->vid_hdr.type = SYNTHVID_RESOLUTION_REQUEST;
> -	msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
> -		sizeof(struct synthvid_supported_resolution_req);
> -
> -	msg->resolution_req.maximum_resolution_count =
> -		SYNTHVID_MAX_RESOLUTION_COUNT;
> -	synthvid_send(hdev, msg);
> -
> -	t = wait_for_completion_timeout(&par->wait, VSP_TIMEOUT);
> -	if (!t) {
> -		pr_err("Time out on waiting resolution response\n");
> -		ret = -ETIMEDOUT;
> -		goto out;
> -	}
> -
> -	if (msg->resolution_resp.resolution_count == 0) {
> -		pr_err("No supported resolutions\n");
> -		ret = -ENODEV;
> -		goto out;
> -	}
> -
> -	index = msg->resolution_resp.default_resolution_index;
> -	if (index >= msg->resolution_resp.resolution_count) {
> -		pr_err("Invalid resolution index: %d\n", index);
> -		ret = -ENODEV;
> -		goto out;
> -	}
> -
> -	screen_width =
> -		msg->resolution_resp.supported_resolution[index].width;
> -	screen_height =
> -		msg->resolution_resp.supported_resolution[index].height;
> -
> -out:
> -	return ret;
> -}
> -
> -/* Connect to VSP (Virtual Service Provider) on host */
> -static int synthvid_connect_vsp(struct hv_device *hdev)
> -{
> -	struct fb_info *info = hv_get_drvdata(hdev);
> -	struct hvfb_par *par = info->par;
> -	int ret;
> -
> -	ret = vmbus_open(hdev->channel, RING_BUFSIZE, RING_BUFSIZE,
> -			 NULL, 0, synthvid_receive, hdev);
> -	if (ret) {
> -		pr_err("Unable to open vmbus channel\n");
> -		return ret;
> -	}
> -
> -	/* Negotiate the protocol version with host */
> -	switch (vmbus_proto_version) {
> -	case VERSION_WIN10:
> -	case VERSION_WIN10_V5:
> -		ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN10);
> -		if (!ret)
> -			break;
> -		fallthrough;
> -	case VERSION_WIN8:
> -	case VERSION_WIN8_1:
> -		ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN8);
> -		break;
> -	default:
> -		ret = synthvid_negotiate_ver(hdev, SYNTHVID_VERSION_WIN10);
> -		break;
> -	}
> -
> -	if (ret) {
> -		pr_err("Synthetic video device version not accepted\n");
> -		goto error;
> -	}
> -
> -	screen_depth = SYNTHVID_DEPTH_WIN8;
> -	if (synthvid_ver_ge(par->synthvid_version, SYNTHVID_VERSION_WIN10)) {
> -		ret = synthvid_get_supported_resolution(hdev);
> -		if (ret)
> -			pr_info("Failed to get supported resolution from host, use default\n");
> -	}
> -
> -	screen_fb_size = hdev->channel->offermsg.offer.
> -				mmio_megabytes * 1024 * 1024;
> -
> -	return 0;
> -
> -error:
> -	vmbus_close(hdev->channel);
> -	return ret;
> -}
> -
> -/* Send VRAM and Situation messages to the host */
> -static int synthvid_send_config(struct hv_device *hdev)
> -{
> -	struct fb_info *info = hv_get_drvdata(hdev);
> -	struct hvfb_par *par = info->par;
> -	struct synthvid_msg *msg = (struct synthvid_msg *)par->init_buf;
> -	int ret = 0;
> -	unsigned long t;
> -
> -	/* Send VRAM location */
> -	memset(msg, 0, sizeof(struct synthvid_msg));
> -	msg->vid_hdr.type = SYNTHVID_VRAM_LOCATION;
> -	msg->vid_hdr.size = sizeof(struct synthvid_msg_hdr) +
> -		sizeof(struct synthvid_vram_location);
> -	msg->vram.user_ctx = msg->vram.vram_gpa = par->mmio_pp;
> -	msg->vram.is_vram_gpa_specified = 1;
> -	synthvid_send(hdev, msg);
> -
> -	t = wait_for_completion_timeout(&par->wait, VSP_TIMEOUT);
> -	if (!t) {
> -		pr_err("Time out on waiting vram location ack\n");
> -		ret = -ETIMEDOUT;
> -		goto out;
> -	}
> -	if (msg->vram_ack.user_ctx != par->mmio_pp) {
> -		pr_err("Unable to set VRAM location\n");
> -		ret = -ENODEV;
> -		goto out;
> -	}
> -
> -	/* Send pointer and situation update */
> -	synthvid_send_ptr(hdev);
> -	synthvid_send_situ(hdev);
> -
> -out:
> -	return ret;
> -}
> -
> -
> -/*
> - * Delayed work callback:
> - * It is scheduled to call whenever update request is received and it has
> - * not been called in last HVFB_ONDEMAND_THROTTLE time interval.
> - */
> -static void hvfb_update_work(struct work_struct *w)
> -{
> -	struct hvfb_par *par = container_of(w, struct hvfb_par, dwork.work);
> -	struct fb_info *info = par->info;
> -	unsigned long flags;
> -	int x1, x2, y1, y2;
> -	int j;
> -
> -	spin_lock_irqsave(&par->delayed_refresh_lock, flags);
> -	/* Reset the request flag */
> -	par->delayed_refresh = false;
> -
> -	/* Store the dirty rectangle to local variables */
> -	x1 = par->x1;
> -	x2 = par->x2;
> -	y1 = par->y1;
> -	y2 = par->y2;
> -
> -	/* Clear dirty rectangle */
> -	par->x1 = par->y1 = INT_MAX;
> -	par->x2 = par->y2 = 0;
> -
> -	spin_unlock_irqrestore(&par->delayed_refresh_lock, flags);
> -
> -	if (x1 > info->var.xres || x2 > info->var.xres ||
> -	    y1 > info->var.yres || y2 > info->var.yres || x2 <= x1)
> -		return;
> -
> -	/* Copy the dirty rectangle to frame buffer memory */
> -	if (par->need_docopy)
> -		for (j = y1; j < y2; j++)
> -			hvfb_docopy(par,
> -				    j * info->fix.line_length +
> -				    (x1 * screen_depth / 8),
> -				    (x2 - x1) * screen_depth / 8);
> -
> -	/* Refresh */
> -	if (par->fb_ready && par->update)
> -		synthvid_update(info, x1, y1, x2, y2);
> -}
> -
> -/*
> - * Control the on-demand refresh frequency. It schedules a delayed
> - * screen update if it has not yet.
> - */
> -static void hvfb_ondemand_refresh_throttle(struct hvfb_par *par,
> -					   int x1, int y1, int w, int h)
> -{
> -	unsigned long flags;
> -	int x2 = x1 + w;
> -	int y2 = y1 + h;
> -
> -	spin_lock_irqsave(&par->delayed_refresh_lock, flags);
> -
> -	/* Merge dirty rectangle */
> -	par->x1 = min_t(int, par->x1, x1);
> -	par->y1 = min_t(int, par->y1, y1);
> -	par->x2 = max_t(int, par->x2, x2);
> -	par->y2 = max_t(int, par->y2, y2);
> -
> -	/* Schedule a delayed screen update if not yet */
> -	if (par->delayed_refresh == false) {
> -		schedule_delayed_work(&par->dwork,
> -				      HVFB_ONDEMAND_THROTTLE);
> -		par->delayed_refresh = true;
> -	}
> -
> -	spin_unlock_irqrestore(&par->delayed_refresh_lock, flags);
> -}
> -
> -static int hvfb_on_panic(struct notifier_block *nb,
> -			 unsigned long e, void *p)
> -{
> -	struct hv_device *hdev;
> -	struct hvfb_par *par;
> -	struct fb_info *info;
> -
> -	par = container_of(nb, struct hvfb_par, hvfb_panic_nb);
> -	info = par->info;
> -	hdev = device_to_hv_device(info->device);
> -
> -	if (hv_ringbuffer_spinlock_busy(hdev->channel))
> -		return NOTIFY_DONE;
> -
> -	par->synchronous_fb = true;
> -	if (par->need_docopy)
> -		hvfb_docopy(par, 0, dio_fb_size);
> -	synthvid_update(info, 0, 0, INT_MAX, INT_MAX);
> -
> -	return NOTIFY_DONE;
> -}
> -
> -/* Framebuffer operation handlers */
> -
> -static int hvfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
> -{
> -	if (var->xres < HVFB_WIDTH_MIN || var->yres < HVFB_HEIGHT_MIN ||
> -	    var->xres > screen_width || var->yres >  screen_height ||
> -	    var->bits_per_pixel != screen_depth)
> -		return -EINVAL;
> -
> -	var->xres_virtual = var->xres;
> -	var->yres_virtual = var->yres;
> -
> -	return 0;
> -}
> -
> -static int hvfb_set_par(struct fb_info *info)
> -{
> -	struct hv_device *hdev = device_to_hv_device(info->device);
> -
> -	return synthvid_send_situ(hdev);
> -}
> -
> -
> -static inline u32 chan_to_field(u32 chan, struct fb_bitfield *bf)
> -{
> -	return ((chan & 0xffff) >> (16 - bf->length)) << bf->offset;
> -}
> -
> -static int hvfb_setcolreg(unsigned regno, unsigned red, unsigned green,
> -			  unsigned blue, unsigned transp, struct fb_info *info)
> -{
> -	u32 *pal = info->pseudo_palette;
> -
> -	if (regno > 15)
> -		return -EINVAL;
> -
> -	pal[regno] = chan_to_field(red, &info->var.red)
> -		| chan_to_field(green, &info->var.green)
> -		| chan_to_field(blue, &info->var.blue)
> -		| chan_to_field(transp, &info->var.transp);
> -
> -	return 0;
> -}
> -
> -static int hvfb_blank(int blank, struct fb_info *info)
> -{
> -	return 1;	/* get fb_blank to set the colormap to all black */
> -}
> -
> -static void hvfb_ops_damage_range(struct fb_info *info, off_t off, size_t len)
> -{
> -	/* TODO: implement damage handling */
> -}
> -
> -static void hvfb_ops_damage_area(struct fb_info *info, u32 x, u32 y, u32 width, u32 height)
> -{
> -	struct hvfb_par *par = info->par;
> -
> -	if (par->synchronous_fb)
> -		synthvid_update(info, 0, 0, INT_MAX, INT_MAX);
> -	else
> -		hvfb_ondemand_refresh_throttle(par, x, y, width, height);
> -}
> -
> -/*
> - * fb_ops.fb_destroy is called by the last put_fb_info() call at the end
> - * of unregister_framebuffer() or fb_release(). Do any cleanup related to
> - * framebuffer here.
> - */
> -static void hvfb_destroy(struct fb_info *info)
> -{
> -	hvfb_putmem(info);
> -	framebuffer_release(info);
> -}
> -
> -/*
> - * TODO: GEN1 codepaths allocate from system or DMA-able memory. Fix the
> - *       driver to use the _SYSMEM_ or _DMAMEM_ helpers in these cases.
> - */
> -FB_GEN_DEFAULT_DEFERRED_IOMEM_OPS(hvfb_ops,
> -				  hvfb_ops_damage_range,
> -				  hvfb_ops_damage_area)
> -
> -static const struct fb_ops hvfb_ops = {
> -	.owner = THIS_MODULE,
> -	FB_DEFAULT_DEFERRED_OPS(hvfb_ops),
> -	.fb_check_var = hvfb_check_var,
> -	.fb_set_par = hvfb_set_par,
> -	.fb_setcolreg = hvfb_setcolreg,
> -	.fb_blank = hvfb_blank,
> -	.fb_destroy	= hvfb_destroy,
> -};
> -
> -/* Get options from kernel paramenter "video=" */
> -static void hvfb_get_option(struct fb_info *info)
> -{
> -	struct hvfb_par *par = info->par;
> -	char *opt = NULL, *p;
> -	uint x = 0, y = 0;
> -
> -	if (fb_get_options(KBUILD_MODNAME, &opt) || !opt || !*opt)
> -		return;
> -
> -	p = strsep(&opt, "x");
> -	if (!*p || kstrtouint(p, 0, &x) ||
> -	    !opt || !*opt || kstrtouint(opt, 0, &y)) {
> -		pr_err("Screen option is invalid: skipped\n");
> -		return;
> -	}
> -
> -	if (x < HVFB_WIDTH_MIN || y < HVFB_HEIGHT_MIN ||
> -	    (synthvid_ver_ge(par->synthvid_version, SYNTHVID_VERSION_WIN10) &&
> -	    (x * y * screen_depth / 8 > screen_fb_size)) ||
> -	    (par->synthvid_version == SYNTHVID_VERSION_WIN8 &&
> -	     x * y * screen_depth / 8 > SYNTHVID_FB_SIZE_WIN8)) {
> -		pr_err("Screen resolution option is out of range: skipped\n");
> -		return;
> -	}
> -
> -	screen_width = x;
> -	screen_height = y;
> -	return;
> -}
> -
> -/*
> - * Allocate enough contiguous physical memory.
> - * Return physical address if succeeded or -1 if failed.
> - */
> -static phys_addr_t hvfb_get_phymem(struct hv_device *hdev,
> -				   unsigned int request_size)
> -{
> -	struct page *page = NULL;
> -	dma_addr_t dma_handle;
> -	void *vmem;
> -	phys_addr_t paddr = 0;
> -	unsigned int order = get_order(request_size);
> -
> -	if (request_size == 0)
> -		return -1;
> -
> -	if (order <= MAX_PAGE_ORDER) {
> -		/* Call alloc_pages if the size is less than 2^MAX_PAGE_ORDER */
> -		page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
> -		if (!page)
> -			return -1;
> -
> -		paddr = (page_to_pfn(page) << PAGE_SHIFT);
> -	} else {
> -		/* Allocate from CMA */
> -		hdev->device.coherent_dma_mask = DMA_BIT_MASK(64);
> -
> -		vmem = dma_alloc_coherent(&hdev->device,
> -					  round_up(request_size, PAGE_SIZE),
> -					  &dma_handle,
> -					  GFP_KERNEL | __GFP_NOWARN);
> -
> -		if (!vmem)
> -			return -1;
> -
> -		paddr = virt_to_phys(vmem);
> -	}
> -
> -	return paddr;
> -}
> -
> -/* Release contiguous physical memory */
> -static void hvfb_release_phymem(struct device *device,
> -				phys_addr_t paddr, unsigned int size)
> -{
> -	unsigned int order = get_order(size);
> -
> -	if (order <= MAX_PAGE_ORDER)
> -		__free_pages(pfn_to_page(paddr >> PAGE_SHIFT), order);
> -	else
> -		dma_free_coherent(device,
> -				  round_up(size, PAGE_SIZE),
> -				  phys_to_virt(paddr),
> -				  paddr);
> -}
> -
> -
> -/* Get framebuffer memory from Hyper-V video pci space */
> -static int hvfb_getmem(struct hv_device *hdev, struct fb_info *info)
> -{
> -	struct hvfb_par *par = info->par;
> -	struct pci_dev *pdev  = NULL;
> -	void __iomem *fb_virt;
> -	int gen2vm = efi_enabled(EFI_BOOT);
> -	resource_size_t base = 0;
> -	resource_size_t size = 0;
> -	phys_addr_t paddr;
> -	int ret;
> -
> -	if (!gen2vm) {
> -		pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT,
> -			PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
> -		if (!pdev) {
> -			pr_err("Unable to find PCI Hyper-V video\n");
> -			return -ENODEV;
> -		}
> -
> -		base = pci_resource_start(pdev, 0);
> -		size = pci_resource_len(pdev, 0);
> -		aperture_remove_conflicting_devices(base, size, KBUILD_MODNAME);
> -
> -		/*
> -		 * For Gen 1 VM, we can directly use the contiguous memory
> -		 * from VM. If we succeed, deferred IO happens directly
> -		 * on this allocated framebuffer memory, avoiding extra
> -		 * memory copy.
> -		 */
> -		paddr = hvfb_get_phymem(hdev, screen_fb_size);
> -		if (paddr != (phys_addr_t) -1) {
> -			par->mmio_pp = paddr;
> -			par->mmio_vp = par->dio_vp = __va(paddr);
> -
> -			info->fix.smem_start = paddr;
> -			info->fix.smem_len = screen_fb_size;
> -			info->screen_base = par->mmio_vp;
> -			info->screen_size = screen_fb_size;
> -
> -			par->need_docopy = false;
> -			goto getmem_done;
> -		}
> -		pr_info("Unable to allocate enough contiguous physical memory on Gen 1 VM. Using MMIO instead.\n");
> -	} else {
> -		aperture_remove_all_conflicting_devices(KBUILD_MODNAME);
> -	}
> -
> -	/*
> -	 * Cannot use contiguous physical memory, so allocate MMIO space for
> -	 * the framebuffer. At this point in the function, conflicting devices
> -	 * that might have claimed the framebuffer MMIO space based on
> -	 * screen_info.lfb_base must have already been removed so that
> -	 * vmbus_allocate_mmio() does not allocate different MMIO space. If the
> -	 * kdump image were to be loaded using kexec_file_load(), the
> -	 * framebuffer location in the kdump image would be set from
> -	 * screen_info.lfb_base at the time that kdump is enabled. If the
> -	 * framebuffer has moved elsewhere, this could be the wrong location,
> -	 * causing kdump to hang when efifb (for example) loads.
> -	 */
> -	dio_fb_size =
> -		screen_width * screen_height * screen_depth / 8;
> -
> -	ret = vmbus_allocate_mmio(&par->mem, hdev, 0, -1,
> -				  screen_fb_size, 0x100000, true);
> -	if (ret != 0) {
> -		pr_err("Unable to allocate framebuffer memory\n");
> -		goto err1;
> -	}
> -
> -	/*
> -	 * Map the VRAM cacheable for performance. This is also required for
> -	 * VM Connect to display properly for ARM64 Linux VM, as the host also
> -	 * maps the VRAM cacheable.
> -	 */
> -	fb_virt = ioremap_cache(par->mem->start, screen_fb_size);
> -	if (!fb_virt)
> -		goto err2;
> -
> -	/* Allocate memory for deferred IO */
> -	par->dio_vp = vzalloc(round_up(dio_fb_size, PAGE_SIZE));
> -	if (par->dio_vp == NULL)
> -		goto err3;
> -
> -	/* Physical address of FB device */
> -	par->mmio_pp = par->mem->start;
> -	/* Virtual address of FB device */
> -	par->mmio_vp = (unsigned char *) fb_virt;
> -
> -	info->fix.smem_start = par->mem->start;
> -	info->fix.smem_len = dio_fb_size;
> -	info->screen_base = par->dio_vp;
> -	info->screen_size = dio_fb_size;
> -
> -getmem_done:
> -	if (!gen2vm)
> -		pci_dev_put(pdev);
> -
> -	return 0;
> -
> -err3:
> -	iounmap(fb_virt);
> -err2:
> -	vmbus_free_mmio(par->mem->start, screen_fb_size);
> -	par->mem = NULL;
> -err1:
> -	if (!gen2vm)
> -		pci_dev_put(pdev);
> -
> -	return -ENOMEM;
> -}
> -
> -/* Release the framebuffer */
> -static void hvfb_putmem(struct fb_info *info)
> -{
> -	struct hvfb_par *par = info->par;
> -
> -	if (par->need_docopy) {
> -		vfree(par->dio_vp);
> -		iounmap(par->mmio_vp);
> -		vmbus_free_mmio(par->mem->start, screen_fb_size);
> -	} else {
> -		hvfb_release_phymem(info->device, info->fix.smem_start,
> -				    screen_fb_size);
> -	}
> -
> -	par->mem = NULL;
> -}
> -
> -
> -static int hvfb_probe(struct hv_device *hdev,
> -		      const struct hv_vmbus_device_id *dev_id)
> -{
> -	struct fb_info *info;
> -	struct hvfb_par *par;
> -	int ret;
> -
> -	info = framebuffer_alloc(sizeof(struct hvfb_par), &hdev->device);
> -	if (!info)
> -		return -ENOMEM;
> -
> -	par = info->par;
> -	par->info = info;
> -	par->fb_ready = false;
> -	par->need_docopy = true;
> -	init_completion(&par->wait);
> -	INIT_DELAYED_WORK(&par->dwork, hvfb_update_work);
> -
> -	par->delayed_refresh = false;
> -	spin_lock_init(&par->delayed_refresh_lock);
> -	par->x1 = par->y1 = INT_MAX;
> -	par->x2 = par->y2 = 0;
> -
> -	/* Connect to VSP */
> -	hv_set_drvdata(hdev, info);
> -	ret = synthvid_connect_vsp(hdev);
> -	if (ret) {
> -		pr_err("Unable to connect to VSP\n");
> -		goto error1;
> -	}
> -
> -	hvfb_get_option(info);
> -	pr_info("Screen resolution: %dx%d, Color depth: %d, Frame buffer size: %d\n",
> -		screen_width, screen_height, screen_depth, screen_fb_size);
> -
> -	ret = hvfb_getmem(hdev, info);
> -	if (ret) {
> -		pr_err("No memory for framebuffer\n");
> -		goto error2;
> -	}
> -
> -	/* Set up fb_info */
> -	info->var.xres_virtual = info->var.xres = screen_width;
> -	info->var.yres_virtual = info->var.yres = screen_height;
> -	info->var.bits_per_pixel = screen_depth;
> -
> -	if (info->var.bits_per_pixel == 16) {
> -		info->var.red = (struct fb_bitfield){11, 5, 0};
> -		info->var.green = (struct fb_bitfield){5, 6, 0};
> -		info->var.blue = (struct fb_bitfield){0, 5, 0};
> -		info->var.transp = (struct fb_bitfield){0, 0, 0};
> -	} else {
> -		info->var.red = (struct fb_bitfield){16, 8, 0};
> -		info->var.green = (struct fb_bitfield){8, 8, 0};
> -		info->var.blue = (struct fb_bitfield){0, 8, 0};
> -		info->var.transp = (struct fb_bitfield){24, 8, 0};
> -	}
> -
> -	info->var.activate = FB_ACTIVATE_NOW;
> -	info->var.height = -1;
> -	info->var.width = -1;
> -	info->var.vmode = FB_VMODE_NONINTERLACED;
> -
> -	strcpy(info->fix.id, KBUILD_MODNAME);
> -	info->fix.type = FB_TYPE_PACKED_PIXELS;
> -	info->fix.visual = FB_VISUAL_TRUECOLOR;
> -	info->fix.line_length = screen_width * screen_depth / 8;
> -	info->fix.accel = FB_ACCEL_NONE;
> -
> -	info->fbops = &hvfb_ops;
> -	info->pseudo_palette = par->pseudo_palette;
> -
> -	/* Initialize deferred IO */
> -	info->fbdefio = &synthvid_defio;
> -	fb_deferred_io_init(info);
> -
> -	/* Send config to host */
> -	ret = synthvid_send_config(hdev);
> -	if (ret)
> -		goto error;
> -
> -	ret = devm_register_framebuffer(&hdev->device, info);
> -	if (ret) {
> -		pr_err("Unable to register framebuffer\n");
> -		goto error;
> -	}
> -
> -	par->fb_ready = true;
> -
> -	par->synchronous_fb = false;
> -
> -	/*
> -	 * We need to be sure this panic notifier runs _before_ the
> -	 * vmbus disconnect, so order it by priority. It must execute
> -	 * before the function hv_panic_vmbus_unload() [drivers/hv/vmbus_drv.c],
> -	 * which is almost at the end of list, with priority = INT_MIN + 1.
> -	 */
> -	par->hvfb_panic_nb.notifier_call = hvfb_on_panic;
> -	par->hvfb_panic_nb.priority = INT_MIN + 10;
> -	atomic_notifier_chain_register(&panic_notifier_list,
> -				       &par->hvfb_panic_nb);
> -
> -	return 0;
> -
> -error:
> -	fb_deferred_io_cleanup(info);
> -	hvfb_putmem(info);
> -error2:
> -	vmbus_close(hdev->channel);
> -error1:
> -	cancel_delayed_work_sync(&par->dwork);
> -	hv_set_drvdata(hdev, NULL);
> -	framebuffer_release(info);
> -	return ret;
> -}
> -
> -static void hvfb_remove(struct hv_device *hdev)
> -{
> -	struct fb_info *info = hv_get_drvdata(hdev);
> -	struct hvfb_par *par = info->par;
> -
> -	atomic_notifier_chain_unregister(&panic_notifier_list,
> -					 &par->hvfb_panic_nb);
> -
> -	par->update = false;
> -	par->fb_ready = false;
> -
> -	fb_deferred_io_cleanup(info);
> -
> -	cancel_delayed_work_sync(&par->dwork);
> -
> -	vmbus_close(hdev->channel);
> -	hv_set_drvdata(hdev, NULL);
> -}
> -
> -static int hvfb_suspend(struct hv_device *hdev)
> -{
> -	struct fb_info *info = hv_get_drvdata(hdev);
> -	struct hvfb_par *par = info->par;
> -
> -	console_lock();
> -
> -	/* 1 means do suspend */
> -	fb_set_suspend(info, 1);
> -
> -	cancel_delayed_work_sync(&par->dwork);
> -	cancel_delayed_work_sync(&info->deferred_work);
> -
> -	par->update_saved = par->update;
> -	par->update = false;
> -	par->fb_ready = false;
> -
> -	vmbus_close(hdev->channel);
> -
> -	console_unlock();
> -
> -	return 0;
> -}
> -
> -static int hvfb_resume(struct hv_device *hdev)
> -{
> -	struct fb_info *info = hv_get_drvdata(hdev);
> -	struct hvfb_par *par = info->par;
> -	int ret;
> -
> -	console_lock();
> -
> -	ret = synthvid_connect_vsp(hdev);
> -	if (ret != 0)
> -		goto out;
> -
> -	ret = synthvid_send_config(hdev);
> -	if (ret != 0) {
> -		vmbus_close(hdev->channel);
> -		goto out;
> -	}
> -
> -	par->fb_ready = true;
> -	par->update = par->update_saved;
> -
> -	schedule_delayed_work(&info->deferred_work, info->fbdefio->delay);
> -	schedule_delayed_work(&par->dwork, HVFB_UPDATE_DELAY);
> -
> -	/* 0 means do resume */
> -	fb_set_suspend(info, 0);
> -
> -out:
> -	console_unlock();
> -
> -	return ret;
> -}
> -
> -
> -static const struct pci_device_id pci_stub_id_table[] = {
> -	{
> -		.vendor      = PCI_VENDOR_ID_MICROSOFT,
> -		.device      = PCI_DEVICE_ID_HYPERV_VIDEO,
> -	},
> -	{ /* end of list */ }
> -};
> -
> -static const struct hv_vmbus_device_id id_table[] = {
> -	/* Synthetic Video Device GUID */
> -	{HV_SYNTHVID_GUID},
> -	{}
> -};
> -
> -MODULE_DEVICE_TABLE(pci, pci_stub_id_table);
> -MODULE_DEVICE_TABLE(vmbus, id_table);
> -
> -static struct hv_driver hvfb_drv = {
> -	.name = KBUILD_MODNAME,
> -	.id_table = id_table,
> -	.probe = hvfb_probe,
> -	.remove = hvfb_remove,
> -	.suspend = hvfb_suspend,
> -	.resume = hvfb_resume,
> -	.driver = {
> -		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
> -	},
> -};
> -
> -static int hvfb_pci_stub_probe(struct pci_dev *pdev,
> -			       const struct pci_device_id *ent)
> -{
> -	return 0;
> -}
> -
> -static void hvfb_pci_stub_remove(struct pci_dev *pdev)
> -{
> -}
> -
> -static struct pci_driver hvfb_pci_stub_driver = {
> -	.name =		KBUILD_MODNAME,
> -	.id_table =	pci_stub_id_table,
> -	.probe =	hvfb_pci_stub_probe,
> -	.remove =	hvfb_pci_stub_remove,
> -	.driver = {
> -		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
> -	}
> -};
> -
> -static int __init hvfb_drv_init(void)
> -{
> -	int ret;
> -
> -	if (fb_modesetting_disabled("hyper_fb"))
> -		return -ENODEV;
> -
> -	ret = vmbus_driver_register(&hvfb_drv);
> -	if (ret != 0)
> -		return ret;
> -
> -	ret = pci_register_driver(&hvfb_pci_stub_driver);
> -	if (ret != 0) {
> -		vmbus_driver_unregister(&hvfb_drv);
> -		return ret;
> -	}
> -
> -	return 0;
> -}
> -
> -static void __exit hvfb_drv_exit(void)
> -{
> -	pci_unregister_driver(&hvfb_pci_stub_driver);
> -	vmbus_driver_unregister(&hvfb_drv);
> -}
> -
> -module_init(hvfb_drv_init);
> -module_exit(hvfb_drv_exit);
> -
> -MODULE_LICENSE("GPL");
> -MODULE_DESCRIPTION("Microsoft Hyper-V Synthetic Video Frame Buffer Driver");

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

RE: [RFC 1/3] fbdev: hyperv_fb: Remove hyperv_fb driver

[Michael Kelley]

From: Thomas Zimmermann <tzimmermann@suse.de> Sent: Wednesday, September 10, 2025 2:36 AM
> 
> Hi
> 
> Am 09.09.25 um 18:58 schrieb Prasanna Kumar T S M:
> > The Hyper-V DRM driver is available since kernel version 5.14 and
> > provides full KMS support along with fbdev emulation via the DRM fbdev
> > helpers. This makes the hyperv_fb driver redundant, remove it.
> 
> I'm all for removing obsolete drivers. But hyperv_drm likely first needs
> to merge the patch at
> https://lore.kernel.org/dri-devel/20250904145806.430568-5-tzimmermann@suse.de/
> It's been tested and works well. If maintainers from Microsoft have a
> look at the patch first, we could possibly land it fairly soon.

Thomas --

My testing of your v3 patch series for vblank timers ended up getting a
WARN_ON after about 3 days of usage. See [1]. So I don't think it's 100%
ready yet.

But I agree we need your synthetic vblank timer support to address the
Hyper-V DRM driver performance issue, before removing the Hyper-V
fbdev driver. (See [2] for a description of the performance issue.)

Second, isn't it customary to mark a driver as deprecated for a period
of time, before removing it entirely? I don't see any documentation
on the deprecation process, but I've seen it done in other cases. If you
grep through all the kernel Kconfig files, you'll see entries tagged with
DEPRECATED. Also the driver should be updated to output a deprecated
message when it loads.

Michael

[1] https://lore.kernel.org/dri-devel/BN7PR02MB4148E80C13605F6EAD2B0A03D40FA@BN7PR02MB4148.namprd02.prod.outlook.com/
[2] https://lore.kernel.org/dri-devel/SN6PR02MB415702B00D6D52B0EE962C98D46CA@SN6PR02MB4157.namprd02.prod.outlook.com/

> 
> Best regards
> Thomas
> 
> >
> > Signed-off-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com>
> > ---
> >   MAINTAINERS                     |    1 -
> >   drivers/video/fbdev/Kconfig     |    8 -
> >   drivers/video/fbdev/Makefile    |    1 -
> >   drivers/video/fbdev/hyperv_fb.c | 1386 -------------------------------
> >   4 files changed, 1396 deletions(-)
> >   delete mode 100644 drivers/video/fbdev/hyperv_fb.c
> >

Re: [RFC 1/3] fbdev: hyperv_fb: Remove hyperv_fb driver

[Thomas Zimmermann]

Hi

Am 10.09.25 um 17:25 schrieb Michael Kelley:
> From: Thomas Zimmermann <tzimmermann@suse.de> Sent: Wednesday, September 10, 2025 2:36 AM
>> Hi
>>
>> Am 09.09.25 um 18:58 schrieb Prasanna Kumar T S M:
>>> The Hyper-V DRM driver is available since kernel version 5.14 and
>>> provides full KMS support along with fbdev emulation via the DRM fbdev
>>> helpers. This makes the hyperv_fb driver redundant, remove it.
>> I'm all for removing obsolete drivers. But hyperv_drm likely first needs
>> to merge the patch at
>> https://lore.kernel.org/dri-devel/20250904145806.430568-5-tzimmermann@suse.de/
>> It's been tested and works well. If maintainers from Microsoft have a
>> look at the patch first, we could possibly land it fairly soon.
> Thomas --
>
> My testing of your v3 patch series for vblank timers ended up getting a
> WARN_ON after about 3 days of usage. See [1]. So I don't think it's 100%
> ready yet.

Yeah, I've seen your message, but didn't have time to investigate yet. 
It might not be that much of an issue.

>
> But I agree we need your synthetic vblank timer support to address the
> Hyper-V DRM driver performance issue, before removing the Hyper-V
> fbdev driver. (See [2] for a description of the performance issue.)
>
> Second, isn't it customary to mark a driver as deprecated for a period
> of time, before removing it entirely? I don't see any documentation
> on the deprecation process, but I've seen it done in other cases. If you
> grep through all the kernel Kconfig files, you'll see entries tagged with
> DEPRECATED. Also the driver should be updated to output a deprecated
> message when it loads.

Sure, we can do that.

Best regards
Thomas

>
> Michael
>
> [1] https://lore.kernel.org/dri-devel/BN7PR02MB4148E80C13605F6EAD2B0A03D40FA@BN7PR02MB4148.namprd02.prod.outlook.com/
> [2] https://lore.kernel.org/dri-devel/SN6PR02MB415702B00D6D52B0EE962C98D46CA@SN6PR02MB4157.namprd02.prod.outlook.com/
>
>> Best regards
>> Thomas
>>
>>> Signed-off-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com>
>>> ---
>>>    MAINTAINERS                     |    1 -
>>>    drivers/video/fbdev/Kconfig     |    8 -
>>>    drivers/video/fbdev/Makefile    |    1 -
>>>    drivers/video/fbdev/hyperv_fb.c | 1386 -------------------------------
>>>    4 files changed, 1396 deletions(-)
>>>    delete mode 100644 drivers/video/fbdev/hyperv_fb.c
>>>

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

Re: [RFC 1/3] fbdev: hyperv_fb: Remove hyperv_fb driver

[Prasanna Kumar T S M]

Hi Michael,

On 10-09-2025 20:55, Michael Kelley wrote:
> From: Thomas Zimmermann <tzimmermann@suse.de> Sent: Wednesday, September 10, 2025 2:36 AM
>>
>> Hi
>>
>> Am 09.09.25 um 18:58 schrieb Prasanna Kumar T S M:
>>> The Hyper-V DRM driver is available since kernel version 5.14 and
>>> provides full KMS support along with fbdev emulation via the DRM fbdev
>>> helpers. This makes the hyperv_fb driver redundant, remove it.
>>
>> I'm all for removing obsolete drivers. But hyperv_drm likely first needs
>> to merge the patch at
>> https://lore.kernel.org/dri-devel/20250904145806.430568-5-tzimmermann@suse.de/
>> It's been tested and works well. If maintainers from Microsoft have a
>> look at the patch first, we could possibly land it fairly soon.
> 
> Thomas --
> 
> My testing of your v3 patch series for vblank timers ended up getting a
> WARN_ON after about 3 days of usage. See [1]. So I don't think it's 100%
> ready yet.
> 
> But I agree we need your synthetic vblank timer support to address the
> Hyper-V DRM driver performance issue, before removing the Hyper-V
> fbdev driver. (See [2] for a description of the performance issue.)
> 
> Second, isn't it customary to mark a driver as deprecated for a period
> of time, before removing it entirely? I don't see any documentation
> on the deprecation process, but I've seen it done in other cases. If you
> grep through all the kernel Kconfig files, you'll see entries tagged with
> DEPRECATED. Also the driver should be updated to output a deprecated
> message when it loads.

Is deprecating the driver a mandatory step?

> Michael
> 
> [1] https://lore.kernel.org/dri-devel/BN7PR02MB4148E80C13605F6EAD2B0A03D40FA@BN7PR02MB4148.namprd02.prod.outlook.com/
> [2] https://lore.kernel.org/dri-devel/SN6PR02MB415702B00D6D52B0EE962C98D46CA@SN6PR02MB4157.namprd02.prod.outlook.com/
> 
>>
>> Best regards
>> Thomas
>>
>>>
>>> Signed-off-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com>
>>> ---
>>>    MAINTAINERS                     |    1 -
>>>    drivers/video/fbdev/Kconfig     |    8 -
>>>    drivers/video/fbdev/Makefile    |    1 -
>>>    drivers/video/fbdev/hyperv_fb.c | 1386 -------------------------------
>>>    4 files changed, 1396 deletions(-)
>>>    delete mode 100644 drivers/video/fbdev/hyperv_fb.c
>>>

RE: [RFC 1/3] fbdev: hyperv_fb: Remove hyperv_fb driver

[Michael Kelley]

From: Prasanna Kumar T S M <ptsm@linux.microsoft.com> Sent: Thursday, September 11, 2025 9:28 AM
> 
> Hi Michael,
> 
> On 10-09-2025 20:55, Michael Kelley wrote:
> > From: Thomas Zimmermann <tzimmermann@suse.de> Sent: Wednesday, September
> 10, 2025 2:36 AM
> >>
> >> Hi
> >>
> >> Am 09.09.25 um 18:58 schrieb Prasanna Kumar T S M:
> >>> The Hyper-V DRM driver is available since kernel version 5.14 and
> >>> provides full KMS support along with fbdev emulation via the DRM fbdev
> >>> helpers. This makes the hyperv_fb driver redundant, remove it.
> >>
> >> I'm all for removing obsolete drivers. But hyperv_drm likely first needs
> >> to merge the patch at
> >> https://lore.kernel.org/dri-devel/20250904145806.430568-5-tzimmermann@suse.de/
> >> It's been tested and works well. If maintainers from Microsoft have a
> >> look at the patch first, we could possibly land it fairly soon.
> >
> > Thomas --
> >
> > My testing of your v3 patch series for vblank timers ended up getting a
> > WARN_ON after about 3 days of usage. See [1]. So I don't think it's 100%
> > ready yet.
> >
> > But I agree we need your synthetic vblank timer support to address the
> > Hyper-V DRM driver performance issue, before removing the Hyper-V
> > fbdev driver. (See [2] for a description of the performance issue.)
> >
> > Second, isn't it customary to mark a driver as deprecated for a period
> > of time, before removing it entirely? I don't see any documentation
> > on the deprecation process, but I've seen it done in other cases. If you
> > grep through all the kernel Kconfig files, you'll see entries tagged with
> > DEPRECATED. Also the driver should be updated to output a deprecated
> > message when it loads.
> 
> Is deprecating the driver a mandatory step?
> 

I'm not aware of a mandatory requirement, at least not in the sense
of it being documented in Documentation/process like other aspects
of the Linux kernel development process. So I would say it's up to
the Maintainers for Hyper-V and FBDEV as to whether the Hyper-V
FB driver should go through a deprecation phase before being
removed.

Of course, the purpose of the deprecation phase is to be "nice"
to users of the driver by giving them some warning that it is going
away. That gives them an opportunity to raise objections, and/or
to do any necessary migration to the replacement driver. I suspect
there aren't many (or any?) users of Hyper-V FB that can't just move
to the Hyper-V DRM driver, but who knows. We might be surprised.

Michael

Re: [RFC 1/3] fbdev: hyperv_fb: Remove hyperv_fb driver

[Thomas Zimmermann]

Hi

Am 12.09.25 um 05:24 schrieb Michael Kelley:
> From: Prasanna Kumar T S M <ptsm@linux.microsoft.com> Sent: Thursday, September 11, 2025 9:28 AM
>> Hi Michael,
>>
>> On 10-09-2025 20:55, Michael Kelley wrote:
>>> From: Thomas Zimmermann <tzimmermann@suse.de> Sent: Wednesday, September
>> 10, 2025 2:36 AM
>>>> Hi
>>>>
>>>> Am 09.09.25 um 18:58 schrieb Prasanna Kumar T S M:
>>>>> The Hyper-V DRM driver is available since kernel version 5.14 and
>>>>> provides full KMS support along with fbdev emulation via the DRM fbdev
>>>>> helpers. This makes the hyperv_fb driver redundant, remove it.
>>>> I'm all for removing obsolete drivers. But hyperv_drm likely first needs
>>>> to merge the patch at
>>>> https://lore.kernel.org/dri-devel/20250904145806.430568-5-tzimmermann@suse.de/
>>>> It's been tested and works well. If maintainers from Microsoft have a
>>>> look at the patch first, we could possibly land it fairly soon.
>>> Thomas --
>>>
>>> My testing of your v3 patch series for vblank timers ended up getting a
>>> WARN_ON after about 3 days of usage. See [1]. So I don't think it's 100%
>>> ready yet.
>>>
>>> But I agree we need your synthetic vblank timer support to address the
>>> Hyper-V DRM driver performance issue, before removing the Hyper-V
>>> fbdev driver. (See [2] for a description of the performance issue.)
>>>
>>> Second, isn't it customary to mark a driver as deprecated for a period
>>> of time, before removing it entirely? I don't see any documentation
>>> on the deprecation process, but I've seen it done in other cases. If you
>>> grep through all the kernel Kconfig files, you'll see entries tagged with
>>> DEPRECATED. Also the driver should be updated to output a deprecated
>>> message when it loads.
>> Is deprecating the driver a mandatory step?
>>
> I'm not aware of a mandatory requirement, at least not in the sense
> of it being documented in Documentation/process like other aspects
> of the Linux kernel development process. So I would say it's up to
> the Maintainers for Hyper-V and FBDEV as to whether the Hyper-V
> FB driver should go through a deprecation phase before being
> removed.
>
> Of course, the purpose of the deprecation phase is to be "nice"
> to users of the driver by giving them some warning that it is going
> away. That gives them an opportunity to raise objections, and/or
> to do any necessary migration to the replacement driver. I suspect
> there aren't many (or any?) users of Hyper-V FB that can't just move
> to the Hyper-V DRM driver, but who knows. We might be surprised.

Let's mark the driver as unmaintained now. There should be a kernel LTS 
release around December [1], after which hyperv-fb could be removed. 
Anyone with hard dependencies on hyperv-fb can remain in the LTS for a 
few more years.

Best regards
Thomas

[1] https://www.kernel.org/category/releases.html

>
> Michael

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)

Re: [RFC 1/3] fbdev: hyperv_fb: Remove hyperv_fb driver

[Prasanna Kumar T S M]

Hi Thomas,

>>> Is deprecating the driver a mandatory step?
>>>
>> I'm not aware of a mandatory requirement, at least not in the sense
>> of it being documented in Documentation/process like other aspects
>> of the Linux kernel development process. So I would say it's up to
>> the Maintainers for Hyper-V and FBDEV as to whether the Hyper-V
>> FB driver should go through a deprecation phase before being
>> removed.
>>
>> Of course, the purpose of the deprecation phase is to be "nice"
>> to users of the driver by giving them some warning that it is going
>> away. That gives them an opportunity to raise objections, and/or
>> to do any necessary migration to the replacement driver. I suspect
>> there aren't many (or any?) users of Hyper-V FB that can't just move
>> to the Hyper-V DRM driver, but who knows. We might be surprised.
> 
> Let's mark the driver as unmaintained now. There should be a kernel LTS 
> release around December [1], after which hyperv-fb could be removed. 
> Anyone with hard dependencies on hyperv-fb can remain in the LTS for a 
> few more years.

Sure, I will send patch deprecating hyperv_fb driver.

Thanks,
Prasanna

Re: [RFC 1/3] fbdev: hyperv_fb: Remove hyperv_fb driver

[Prasanna Kumar T S M]

Hi Thomas,

On 10-09-2025 15:06, Thomas Zimmermann wrote:
> Hi
> 
> Am 09.09.25 um 18:58 schrieb Prasanna Kumar T S M:
>> The Hyper-V DRM driver is available since kernel version 5.14 and
>> provides full KMS support along with fbdev emulation via the DRM fbdev
>> helpers. This makes the hyperv_fb driver redundant, remove it.
> 
> I'm all for removing obsolete drivers. But hyperv_drm likely first needs 
> to merge the patch at https://lore.kernel.org/dri- 
> devel/20250904145806.430568-5-tzimmermann@suse.de/ It's been tested and 
> works well. If maintainers from Microsoft have a look at the patch 
> first, we could possibly land it fairly soon.
> 

I will test those patches on Hyper-V and share the result.

> Best regards
> Thomas
> 

[RFC 2/3] drm/hyperv: Remove reference to hyperv_fb driver

[Prasanna Kumar T S M]

Remove hyperv_fb references as the driver is removed.

Signed-off-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com>
---
 drivers/gpu/drm/Kconfig                   |  3 +--
 drivers/gpu/drm/hyperv/hyperv_drm_proto.c | 15 +++++----------
 2 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index f7ea8e895c0c..a39e5171f107 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -405,8 +405,7 @@ config DRM_HYPERV
 	help
 	 This is a KMS driver for Hyper-V synthetic video device. Choose this
 	 option if you would like to enable drm driver for Hyper-V virtual
-	 machine. Unselect Hyper-V framebuffer driver (CONFIG_FB_HYPERV) so
-	 that DRM driver is used by default.
+	 machine.
 
 	 If M is selected the module will be called hyperv_drm.
 
diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_proto.c b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c
index 013a7829182d..051ecc526832 100644
--- a/drivers/gpu/drm/hyperv/hyperv_drm_proto.c
+++ b/drivers/gpu/drm/hyperv/hyperv_drm_proto.c
@@ -1,8 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright 2021 Microsoft
- *
- * Portions of this code is derived from hyperv_fb.c
  */
 
 #include <linux/hyperv.h>
@@ -304,16 +302,13 @@ int hyperv_update_situation(struct hv_device *hdev, u8 active, u32 bpp,
  * but the Hyper-V host still draws a point as an extra mouse pointer,
  * which is unwanted, especially when Xorg is running.
  *
- * The hyperv_fb driver uses synthvid_send_ptr() to hide the unwanted
- * pointer, by setting msg.ptr_pos.is_visible = 1 and setting the
- * msg.ptr_shape.data. Note: setting msg.ptr_pos.is_visible to 0 doesn't
+ * Hide the unwanted pointer, by setting msg.ptr_pos.is_visible = 1 and setting
+ * the msg.ptr_shape.data. Note: setting msg.ptr_pos.is_visible to 0 doesn't
  * work in tests.
  *
- * Copy synthvid_send_ptr() to hyperv_drm and rename it to
- * hyperv_hide_hw_ptr(). Note: hyperv_hide_hw_ptr() is also called in the
- * handler of the SYNTHVID_FEATURE_CHANGE event, otherwise the host still
- * draws an extra unwanted mouse pointer after the VM Connection window is
- * closed and reopened.
+ * The hyperv_hide_hw_ptr() is also called in the handler of the
+ * SYNTHVID_FEATURE_CHANGE event, otherwise the host still draws an extra
+ * unwanted mouse pointer after the VM Connection window is closed and reopened.
  */
 int hyperv_hide_hw_ptr(struct hv_device *hdev)
 {
-- 
2.49.0

[RFC 3/3] Drivers: hv: vmbus_drv: Remove reference to hyperv_fb

[Prasanna Kumar T S M]

Remove hyperv_fb references as the driver is removed.

Signed-off-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com>
---
 drivers/hv/vmbus_drv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 2ed5a1e89d69..5ed523b4e951 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2298,8 +2298,8 @@ static void __maybe_unused vmbus_reserve_fb(void)
 		}
 
 		/*
-		 * Release the PCI device so hyperv_drm or hyperv_fb driver can
-		 * grab it later.
+		 * Release the PCI device so hyperv_drm driver can grab it
+		 * later.
 		 */
 		pci_dev_put(pdev);
 	}
-- 
2.49.0