drm: Add Grain Media GM12U320 driver v2

Add a modesetting driver for Grain Media GM12U320 based devices
(primarily Acer C120 projector, but there may be compatible devices).

This is based on the fb driver from Viacheslav Nurmekhamitov:
https://github.com/slavrn/gm12u320

This driver uses drm_simple_display_pipe to deal with all the atomic
stuff, gem_shmem_helper functions for buffer management and
drm_fbdev_generic_setup for fbdev emulation, so that leaves the driver
itself with only the actual code for talking to the gm12u320 chip,
leading to a nice simple and clean driver.

Changes in v2:
-Add drm-misc tree to MAINTAINERS
-Drop mode_config.preferred_depth = 24 / fix fbdev support
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190721132525.10396-1-hdegoede@redhat.com

MAINTAINERS

@@ -5015,6 +5015,12 @@ S:	Maintained
 F:	drivers/gpu/drm/panel/panel-feiyang-fy07024di26a30d.c
 F:	Documentation/devicetree/bindings/display/panel/feiyang,fy07024di26a30d.txt
 
+DRM DRIVER FOR GRAIN MEDIA GM12U320 PROJECTORS
+M:	Hans de Goede <hdegoede@redhat.com>
+T:	git git://anongit.freedesktop.org/drm/drm-misc
+S:	Maintained
+F:	drivers/gpu/drm/gm12u320/
+
 DRM DRIVER FOR ILITEK ILI9225 PANELS
 M:	David Lechner <david@lechnology.com>
 S:	Maintained

drivers/gpu/drm/Kconfig

@@ -354,6 +354,8 @@ source "drivers/gpu/drm/aspeed/Kconfig"
 
 source "drivers/gpu/drm/mcde/Kconfig"
 
+source "drivers/gpu/drm/gm12u320/Kconfig"
+
 # Keep legacy drivers last
 
 menuconfig DRM_LEGACY

drivers/gpu/drm/Makefile

@@ -120,3 +120,4 @@ obj-$(CONFIG_DRM_LIMA)  += lima/
 obj-$(CONFIG_DRM_PANFROST) += panfrost/
 obj-$(CONFIG_DRM_ASPEED_GFX) += aspeed/
 obj-$(CONFIG_DRM_MCDE) += mcde/
+obj-$(CONFIG_DRM_GM12U320) += gm12u320/

drivers/gpu/drm/gm12u320/Kconfig

+# SPDX-License-Identifier: GPL-2.0+
+config DRM_GM12U320
+	tristate "GM12U320 driver for USB projectors"
+	depends on DRM && USB
+	select DRM_KMS_HELPER
+	select DRM_GEM_SHMEM_HELPER
+	help
+	 This is a KMS driver for projectors which use the GM12U320 chipset
+	 for video transfer over USB2/3, such as the Acer C120 mini projector.

drivers/gpu/drm/gm12u320/Makefile

+# SPDX-License-Identifier: GPL-2.0+
+obj-$(CONFIG_DRM_GM12U320) += gm12u320.o

drivers/gpu/drm/gm12u320/gm12u320.c

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright 2019 Hans de Goede <hdegoede@redhat.com>
+ */
+
+#include <linux/dma-buf.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_atomic_state_helper.h>
+#include <drm/drm_connector.h>
+#include <drm/drm_damage_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_file.h>
+#include <drm/drm_format_helper.h>
+#include <drm/drm_fourcc.h>
+#include <drm/drm_gem_shmem_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_ioctl.h>
+#include <drm/drm_modeset_helper_vtables.h>
+#include <drm/drm_probe_helper.h>
+#include <drm/drm_simple_kms_helper.h>
+#include <drm/drm_vblank.h>
+
+static bool eco_mode;
+module_param(eco_mode, bool, 0644);
+MODULE_PARM_DESC(eco_mode, "Turn on Eco mode (less bright, more silent)");
+
+#define DRIVER_NAME		"gm12u320"
+#define DRIVER_DESC		"Grain Media GM12U320 USB projector display"
+#define DRIVER_DATE		"2019"
+#define DRIVER_MAJOR		1
+#define DRIVER_MINOR		0
+#define DRIVER_PATCHLEVEL	1
+
+/*
+ * The DLP has an actual width of 854 pixels, but that is not a multiple
+ * of 8, breaking things left and right, so we export a width of 848.
+ */
+#define GM12U320_USER_WIDTH		848
+#define GM12U320_REAL_WIDTH		854
+#define GM12U320_HEIGHT			480
+
+#define GM12U320_BLOCK_COUNT		20
+
+#define MISC_RCV_EPT			1
+#define DATA_RCV_EPT			2
+#define DATA_SND_EPT			3
+#define MISC_SND_EPT			4
+
+#define DATA_BLOCK_HEADER_SIZE		84
+#define DATA_BLOCK_CONTENT_SIZE		64512
+#define DATA_BLOCK_FOOTER_SIZE		20
+#define DATA_BLOCK_SIZE			(DATA_BLOCK_HEADER_SIZE + \
+					 DATA_BLOCK_CONTENT_SIZE + \
+					 DATA_BLOCK_FOOTER_SIZE)
+#define DATA_LAST_BLOCK_CONTENT_SIZE	4032
+#define DATA_LAST_BLOCK_SIZE		(DATA_BLOCK_HEADER_SIZE + \
+					 DATA_LAST_BLOCK_CONTENT_SIZE + \
+					 DATA_BLOCK_FOOTER_SIZE)
+
+#define CMD_SIZE			31
+#define READ_STATUS_SIZE		13
+#define MISC_VALUE_SIZE			4
+
+#define CMD_TIMEOUT			msecs_to_jiffies(200)
+#define DATA_TIMEOUT			msecs_to_jiffies(1000)
+#define IDLE_TIMEOUT			msecs_to_jiffies(2000)
+#define FIRST_FRAME_TIMEOUT		msecs_to_jiffies(2000)
+
+#define MISC_REQ_GET_SET_ECO_A		0xff
+#define MISC_REQ_GET_SET_ECO_B		0x35
+/* Windows driver does once every second, with arg d = 1, other args 0 */
+#define MISC_REQ_UNKNOWN1_A		0xff
+#define MISC_REQ_UNKNOWN1_B		0x38
+/* Windows driver does this on init, with arg a, b = 0, c = 0xa0, d = 4 */
+#define MISC_REQ_UNKNOWN2_A		0xa5
+#define MISC_REQ_UNKNOWN2_B		0x00
+
+struct gm12u320_device {
+	struct drm_device	         dev;
+	struct drm_simple_display_pipe   pipe;
+	struct drm_connector	         conn;
+	struct usb_device               *udev;
+	unsigned char                   *cmd_buf;
+	unsigned char                   *data_buf[GM12U320_BLOCK_COUNT];
+	bool                             pipe_enabled;
+	struct {
+		bool                     run;
+		struct workqueue_struct *workq;
+		struct work_struct       work;
+		wait_queue_head_t        waitq;
+		struct mutex             lock;
+		struct drm_framebuffer  *fb;
+		struct drm_rect          rect;
+	} fb_update;
+};
+
+static const char cmd_data[CMD_SIZE] = {
+	0x55, 0x53, 0x42, 0x43, 0x00, 0x00, 0x00, 0x00,
+	0x68, 0xfc, 0x00, 0x00, 0x00, 0x00, 0x10, 0xff,
+	0x00, 0x00, 0x00, 0x00, 0xfc, 0x00, 0x80, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+};
+
+static const char cmd_draw[CMD_SIZE] = {
+	0x55, 0x53, 0x42, 0x43, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x10, 0xfe,
+	0x00, 0x00, 0x00, 0xc0, 0xd1, 0x05, 0x00, 0x40,
+	0x00, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00
+};
+
+static const char cmd_misc[CMD_SIZE] = {
+	0x55, 0x53, 0x42, 0x43, 0x00, 0x00, 0x00, 0x00,
+	0x04, 0x00, 0x00, 0x00, 0x80, 0x01, 0x10, 0xfd,
+	0x00, 0x00, 0x00, 0xc0, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+};
+
+static const char data_block_header[DATA_BLOCK_HEADER_SIZE] = {
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0xfb, 0x14, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x04, 0x15, 0x00, 0x00, 0xfc, 0x00, 0x00,
+	0x01, 0x00, 0x00, 0xdb
+};
+
+static const char data_last_block_header[DATA_BLOCK_HEADER_SIZE] = {
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0xfb, 0x14, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x2a, 0x00, 0x20, 0x00, 0xc0, 0x0f, 0x00, 0x00,
+	0x01, 0x00, 0x00, 0xd7
+};
+
+static const char data_block_footer[DATA_BLOCK_FOOTER_SIZE] = {
+	0xfb, 0x14, 0x02, 0x20, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x80, 0x00, 0x00, 0x4f
+};
+
+static int gm12u320_usb_alloc(struct gm12u320_device *gm12u320)
+{
+	int i, block_size;
+	const char *hdr;
+
+	gm12u320->cmd_buf = kmalloc(CMD_SIZE, GFP_KERNEL);
+	if (!gm12u320->cmd_buf)
+		return -ENOMEM;
+
+	for (i = 0; i < GM12U320_BLOCK_COUNT; i++) {
+		if (i == GM12U320_BLOCK_COUNT - 1) {
+			block_size = DATA_LAST_BLOCK_SIZE;
+			hdr = data_last_block_header;
+		} else {
+			block_size = DATA_BLOCK_SIZE;
+			hdr = data_block_header;
+		}
+
+		gm12u320->data_buf[i] = kzalloc(block_size, GFP_KERNEL);
+		if (!gm12u320->data_buf[i])
+			return -ENOMEM;
+
+		memcpy(gm12u320->data_buf[i], hdr, DATA_BLOCK_HEADER_SIZE);
+		memcpy(gm12u320->data_buf[i] +
+				(block_size - DATA_BLOCK_FOOTER_SIZE),
+		       data_block_footer, DATA_BLOCK_FOOTER_SIZE);
+	}
+
+	gm12u320->fb_update.workq = create_singlethread_workqueue(DRIVER_NAME);
+	if (!gm12u320->fb_update.workq)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static void gm12u320_usb_free(struct gm12u320_device *gm12u320)
+{
+	int i;
+
+	if (gm12u320->fb_update.workq)
+		destroy_workqueue(gm12u320->fb_update.workq);
+
+	for (i = 0; i < GM12U320_BLOCK_COUNT; i++)
+		kfree(gm12u320->data_buf[i]);
+
+	kfree(gm12u320->cmd_buf);
+}
+
+static int gm12u320_misc_request(struct gm12u320_device *gm12u320,
+				 u8 req_a, u8 req_b,
+				 u8 arg_a, u8 arg_b, u8 arg_c, u8 arg_d)
+{
+	int ret, len;
+
+	memcpy(gm12u320->cmd_buf, &cmd_misc, CMD_SIZE);
+	gm12u320->cmd_buf[20] = req_a;
+	gm12u320->cmd_buf[21] = req_b;
+	gm12u320->cmd_buf[22] = arg_a;
+	gm12u320->cmd_buf[23] = arg_b;
+	gm12u320->cmd_buf[24] = arg_c;
+	gm12u320->cmd_buf[25] = arg_d;
+
+	/* Send request */
+	ret = usb_bulk_msg(gm12u320->udev,
+			   usb_sndbulkpipe(gm12u320->udev, MISC_SND_EPT),
+			   gm12u320->cmd_buf, CMD_SIZE, &len, CMD_TIMEOUT);
+	if (ret || len != CMD_SIZE) {
+		dev_err(&gm12u320->udev->dev, "Misc. req. error %d\n", ret);
+		return -EIO;
+	}
+
+	/* Read value */
+	ret = usb_bulk_msg(gm12u320->udev,
+			   usb_rcvbulkpipe(gm12u320->udev, MISC_RCV_EPT),
+			   gm12u320->cmd_buf, MISC_VALUE_SIZE, &len,
+			   DATA_TIMEOUT);
+	if (ret || len != MISC_VALUE_SIZE) {
+		dev_err(&gm12u320->udev->dev, "Misc. value error %d\n", ret);
+		return -EIO;
+	}
+	/* cmd_buf[0] now contains the read value, which we don't use */
+
+	/* Read status */
+	ret = usb_bulk_msg(gm12u320->udev,
+			   usb_rcvbulkpipe(gm12u320->udev, MISC_RCV_EPT),
+			   gm12u320->cmd_buf, READ_STATUS_SIZE, &len,
+			   CMD_TIMEOUT);
+	if (ret || len != READ_STATUS_SIZE) {
+		dev_err(&gm12u320->udev->dev, "Misc. status error %d\n", ret);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static void gm12u320_32bpp_to_24bpp_packed(u8 *dst, u8 *src, int len)
+{
+	while (len--) {
+		*dst++ = *src++;
+		*dst++ = *src++;
+		*dst++ = *src++;
+		src++;
+	}
+}
+
+static void gm12u320_copy_fb_to_blocks(struct gm12u320_device *gm12u320)
+{
+	int block, dst_offset, len, remain, ret, x1, x2, y1, y2;
+	struct drm_framebuffer *fb;
+	void *vaddr;
+	u8 *src;
+
+	mutex_lock(&gm12u320->fb_update.lock);
+
+	if (!gm12u320->fb_update.fb)
+		goto unlock;
+
+	fb = gm12u320->fb_update.fb;
+	x1 = gm12u320->fb_update.rect.x1;
+	x2 = gm12u320->fb_update.rect.x2;
+	y1 = gm12u320->fb_update.rect.y1;
+	y2 = gm12u320->fb_update.rect.y2;
+
+	vaddr = drm_gem_shmem_vmap(fb->obj[0]);
+	if (IS_ERR(vaddr)) {
+		DRM_ERROR("failed to vmap fb: %ld\n", PTR_ERR(vaddr));
+		goto put_fb;
+	}
+
+	if (fb->obj[0]->import_attach) {
+		ret = dma_buf_begin_cpu_access(
+			fb->obj[0]->import_attach->dmabuf, DMA_FROM_DEVICE);
+		if (ret) {
+			DRM_ERROR("dma_buf_begin_cpu_access err: %d\n", ret);
+			goto vunmap;
+		}
+	}
+
+	src = vaddr + y1 * fb->pitches[0] + x1 * 4;
+
+	x1 += (GM12U320_REAL_WIDTH - GM12U320_USER_WIDTH) / 2;
+	x2 += (GM12U320_REAL_WIDTH - GM12U320_USER_WIDTH) / 2;
+
+	for (; y1 < y2; y1++) {
+		remain = 0;
+		len = (x2 - x1) * 3;
+		dst_offset = (y1 * GM12U320_REAL_WIDTH + x1) * 3;
+		block = dst_offset / DATA_BLOCK_CONTENT_SIZE;
+		dst_offset %= DATA_BLOCK_CONTENT_SIZE;
+
+		if ((dst_offset + len) > DATA_BLOCK_CONTENT_SIZE) {
+			remain = dst_offset + len - DATA_BLOCK_CONTENT_SIZE;
+			len = DATA_BLOCK_CONTENT_SIZE - dst_offset;
+		}
+
+		dst_offset += DATA_BLOCK_HEADER_SIZE;
+		len /= 3;
+
+		gm12u320_32bpp_to_24bpp_packed(
+			gm12u320->data_buf[block] + dst_offset,
+			src, len);
+
+		if (remain) {
+			block++;
+			dst_offset = DATA_BLOCK_HEADER_SIZE;
+			gm12u320_32bpp_to_24bpp_packed(
+				gm12u320->data_buf[block] + dst_offset,
+				src + len * 4, remain / 3);
+		}
+		src += fb->pitches[0];
+	}
+
+	if (fb->obj[0]->import_attach) {
+		ret = dma_buf_end_cpu_access(fb->obj[0]->import_attach->dmabuf,
+					     DMA_FROM_DEVICE);
+		if (ret)
+			DRM_ERROR("dma_buf_end_cpu_access err: %d\n", ret);
+	}
+vunmap:
+	drm_gem_shmem_vunmap(fb->obj[0], vaddr);
+put_fb:
+	drm_framebuffer_put(fb);
+	gm12u320->fb_update.fb = NULL;
+unlock:
+	mutex_unlock(&gm12u320->fb_update.lock);
+}
+
+static int gm12u320_fb_update_ready(struct gm12u320_device *gm12u320)
+{
+	int ret;
+
+	mutex_lock(&gm12u320->fb_update.lock);
+	ret = !gm12u320->fb_update.run || gm12u320->fb_update.fb != NULL;
+	mutex_unlock(&gm12u320->fb_update.lock);
+
+	return ret;
+}
+
+static void gm12u320_fb_update_work(struct work_struct *work)
+{
+	struct gm12u320_device *gm12u320 =
+		container_of(work, struct gm12u320_device, fb_update.work);
+	int draw_status_timeout = FIRST_FRAME_TIMEOUT;
+	int block, block_size, len;
+	int frame = 0;
+	int ret = 0;
+
+	while (gm12u320->fb_update.run) {
+		gm12u320_copy_fb_to_blocks(gm12u320);
+
+		for (block = 0; block < GM12U320_BLOCK_COUNT; block++) {
+			if (block == GM12U320_BLOCK_COUNT - 1)
+				block_size = DATA_LAST_BLOCK_SIZE;
+			else
+				block_size = DATA_BLOCK_SIZE;
+
+			/* Send data command to device */
+			memcpy(gm12u320->cmd_buf, cmd_data, CMD_SIZE);
+			gm12u320->cmd_buf[8] = block_size & 0xff;
+			gm12u320->cmd_buf[9] = block_size >> 8;
+			gm12u320->cmd_buf[20] = 0xfc - block * 4;
+			gm12u320->cmd_buf[21] = block | (frame << 7);
+
+			ret = usb_bulk_msg(gm12u320->udev,
+				usb_sndbulkpipe(gm12u320->udev, DATA_SND_EPT),
+				gm12u320->cmd_buf, CMD_SIZE, &len,
+				CMD_TIMEOUT);
+			if (ret || len != CMD_SIZE)
+				goto err;
+
+			/* Send data block to device */
+			ret = usb_bulk_msg(gm12u320->udev,
+				usb_sndbulkpipe(gm12u320->udev, DATA_SND_EPT),
+				gm12u320->data_buf[block], block_size,
+				&len, DATA_TIMEOUT);
+			if (ret || len != block_size)
+				goto err;
+
+			/* Read status */
+			ret = usb_bulk_msg(gm12u320->udev,
+				usb_rcvbulkpipe(gm12u320->udev, DATA_RCV_EPT),
+				gm12u320->cmd_buf, READ_STATUS_SIZE, &len,
+				CMD_TIMEOUT);
+			if (ret || len != READ_STATUS_SIZE)
+				goto err;
+		}
+
+		/* Send draw command to device */
+		memcpy(gm12u320->cmd_buf, cmd_draw, CMD_SIZE);
+		ret = usb_bulk_msg(gm12u320->udev,
+			usb_sndbulkpipe(gm12u320->udev, DATA_SND_EPT),
+			gm12u320->cmd_buf, CMD_SIZE, &len, CMD_TIMEOUT);
+		if (ret || len != CMD_SIZE)
+			goto err;
+
+		/* Read status */
+		ret = usb_bulk_msg(gm12u320->udev,
+			usb_rcvbulkpipe(gm12u320->udev, DATA_RCV_EPT),
+			gm12u320->cmd_buf, READ_STATUS_SIZE, &len,
+			draw_status_timeout);
+		if (ret || len != READ_STATUS_SIZE)
+			goto err;
+
+		draw_status_timeout = CMD_TIMEOUT;
+		frame = !frame;
+
+		/*
+		 * We must draw a frame every 2s otherwise the projector
+		 * switches back to showing its logo.
+		 */
+		wait_event_timeout(gm12u320->fb_update.waitq,
+				   gm12u320_fb_update_ready(gm12u320),
+				   IDLE_TIMEOUT);
+	}
+	return;
+err:
+	/* Do not log errors caused by module unload or device unplug */
+	if (ret != -ECONNRESET && ret != -ESHUTDOWN)
+		dev_err(&gm12u320->udev->dev, "Frame update error: %d\n", ret);
+}
+
+static void gm12u320_fb_mark_dirty(struct drm_framebuffer *fb,
+				   struct drm_rect *dirty)
+{
+	struct gm12u320_device *gm12u320 = fb->dev->dev_private;
+	struct drm_framebuffer *old_fb = NULL;
+	bool wakeup = false;
+
+	mutex_lock(&gm12u320->fb_update.lock);
+
+	if (gm12u320->fb_update.fb != fb) {
+		old_fb = gm12u320->fb_update.fb;
+		drm_framebuffer_get(fb);
+		gm12u320->fb_update.fb = fb;
+		gm12u320->fb_update.rect = *dirty;
+		wakeup = true;
+	} else {
+		struct drm_rect *rect = &gm12u320->fb_update.rect;
+
+		rect->x1 = min(rect->x1, dirty->x1);
+		rect->y1 = min(rect->y1, dirty->y1);
+		rect->x2 = max(rect->x2, dirty->x2);
+		rect->y2 = max(rect->y2, dirty->y2);
+	}
+
+	mutex_unlock(&gm12u320->fb_update.lock);
+
+	if (wakeup)
+		wake_up(&gm12u320->fb_update.waitq);
+
+	if (old_fb)
+		drm_framebuffer_put(old_fb);
+}
+
+static void gm12u320_start_fb_update(struct gm12u320_device *gm12u320)
+{
+	mutex_lock(&gm12u320->fb_update.lock);
+	gm12u320->fb_update.run = true;
+	mutex_unlock(&gm12u320->fb_update.lock);
+
+	queue_work(gm12u320->fb_update.workq, &gm12u320->fb_update.work);
+}
+
+static void gm12u320_stop_fb_update(struct gm12u320_device *gm12u320)
+{
+	mutex_lock(&gm12u320->fb_update.lock);
+	gm12u320->fb_update.run = false;
+	mutex_unlock(&gm12u320->fb_update.lock);
+
+	wake_up(&gm12u320->fb_update.waitq);
+	cancel_work_sync(&gm12u320->fb_update.work);
+
+	mutex_lock(&gm12u320->fb_update.lock);
+	if (gm12u320->fb_update.fb) {
+		drm_framebuffer_put(gm12u320->fb_update.fb);
+		gm12u320->fb_update.fb = NULL;
+	}
+	mutex_unlock(&gm12u320->fb_update.lock);
+}
+
+static int gm12u320_set_ecomode(struct gm12u320_device *gm12u320)
+{
+	return gm12u320_misc_request(gm12u320, MISC_REQ_GET_SET_ECO_A,
+				     MISC_REQ_GET_SET_ECO_B, 0x01 /* set */,
+				     eco_mode ? 0x01 : 0x00, 0x00, 0x01);
+}
+
+/* ------------------------------------------------------------------ */
+/* gm12u320 connector						      */
+
+/*
+ * We use fake EDID info so that userspace know that it is dealing with
+ * an Acer projector, rather then listing this as an "unknown" monitor.
+ * Note this assumes this driver is only ever used with the Acer C120, if we
+ * add support for other devices the vendor and model should be parameterized.
+ */
+static struct edid gm12u320_edid = {
+	.header		= { 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00 },
+	.mfg_id		= { 0x04, 0x72 },	/* "ACR" */
+	.prod_code	= { 0x20, 0xc1 },	/* C120h */
+	.serial		= 0xaa55aa55,
+	.mfg_week	= 1,
+	.mfg_year	= 16,
+	.version	= 1,			/* EDID 1.3 */
+	.revision	= 3,			/* EDID 1.3 */
+	.input		= 0x08,			/* Analog input */
+	.features	= 0x0a,			/* Pref timing in DTD 1 */
+	.standard_timings = { { 1, 1 }, { 1, 1 }, { 1, 1 }, { 1, 1 },
+			      { 1, 1 }, { 1, 1 }, { 1, 1 }, { 1, 1 } },
+	.detailed_timings = { {
+		.pixel_clock = 3383,
+		/* hactive = 848, hblank = 256 */
+		.data.pixel_data.hactive_lo = 0x50,
+		.data.pixel_data.hblank_lo = 0x00,
+		.data.pixel_data.hactive_hblank_hi = 0x31,
+		/* vactive = 480, vblank = 28 */
+		.data.pixel_data.vactive_lo = 0xe0,
+		.data.pixel_data.vblank_lo = 0x1c,
+		.data.pixel_data.vactive_vblank_hi = 0x10,
+		/* hsync offset 40 pw 128, vsync offset 1 pw 4 */
+		.data.pixel_data.hsync_offset_lo = 0x28,
+		.data.pixel_data.hsync_pulse_width_lo = 0x80,
+		.data.pixel_data.vsync_offset_pulse_width_lo = 0x14,
+		.data.pixel_data.hsync_vsync_offset_pulse_width_hi = 0x00,
+		/* Digital separate syncs, hsync+, vsync+ */
+		.data.pixel_data.misc = 0x1e,
+	}, {
+		.pixel_clock = 0,
+		.data.other_data.type = 0xfd, /* Monitor ranges */
+		.data.other_data.data.range.min_vfreq = 59,
+		.data.other_data.data.range.max_vfreq = 61,
+		.data.other_data.data.range.min_hfreq_khz = 29,
+		.data.other_data.data.range.max_hfreq_khz = 32,
+		.data.other_data.data.range.pixel_clock_mhz = 4, /* 40 MHz */
+		.data.other_data.data.range.flags = 0,
+		.data.other_data.data.range.formula.cvt = {
+			0xa0, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20 },
+	}, {
+		.pixel_clock = 0,
+		.data.other_data.type = 0xfc, /* Model string */
+		.data.other_data.data.str.str = {
+			'P', 'r', 'o', 'j', 'e', 'c', 't', 'o', 'r', '\n',
+			' ', ' ',  ' ' },
+	}, {
+		.pixel_clock = 0,
+		.data.other_data.type = 0xfe, /* Unspecified text / padding */
+		.data.other_data.data.str.str = {
+			'\n', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ',
+			' ', ' ',  ' ' },
+	} },
+	.checksum = 0x13,
+};
+
+static int gm12u320_conn_get_modes(struct drm_connector *connector)
+{
+	drm_connector_update_edid_property(connector, &gm12u320_edid);
+	return drm_add_edid_modes(connector, &gm12u320_edid);
+}
+
+static const struct drm_connector_helper_funcs gm12u320_conn_helper_funcs = {
+	.get_modes = gm12u320_conn_get_modes,
+};
+
+static const struct drm_connector_funcs gm12u320_conn_funcs = {
+	.fill_modes = drm_helper_probe_single_connector_modes,
+	.destroy = drm_connector_cleanup,
+	.reset = drm_atomic_helper_connector_reset,
+	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
+};
+
+static int gm12u320_conn_init(struct gm12u320_device *gm12u320)
+{
+	drm_connector_helper_add(&gm12u320->conn, &gm12u320_conn_helper_funcs);
+	return drm_connector_init(&gm12u320->dev, &gm12u320->conn,
+				  &gm12u320_conn_funcs, DRM_MODE_CONNECTOR_VGA);
+}
+
+/* ------------------------------------------------------------------ */
+/* gm12u320 (simple) display pipe				      */
+
+static void gm12u320_pipe_enable(struct drm_simple_display_pipe *pipe,
+				 struct drm_crtc_state *crtc_state,
+				 struct drm_plane_state *plane_state)
+{
+	struct gm12u320_device *gm12u320 = pipe->crtc.dev->dev_private;
+	struct drm_rect rect = { 0, 0, GM12U320_USER_WIDTH, GM12U320_HEIGHT };
+
+	gm12u320_fb_mark_dirty(plane_state->fb, &rect);
+	gm12u320_start_fb_update(gm12u320);
+	gm12u320->pipe_enabled = true;
+}
+
+static void gm12u320_pipe_disable(struct drm_simple_display_pipe *pipe)
+{
+	struct gm12u320_device *gm12u320 = pipe->crtc.dev->dev_private;
+
+	gm12u320_stop_fb_update(gm12u320);
+	gm12u320->pipe_enabled = false;
+}
+
+static void gm12u320_pipe_update(struct drm_simple_display_pipe *pipe,
+				 struct drm_plane_state *old_state)
+{
+	struct drm_plane_state *state = pipe->plane.state;
+	struct drm_crtc *crtc = &pipe->crtc;
+	struct drm_rect rect;
+
+	if (drm_atomic_helper_damage_merged(old_state, state, &rect))
+		gm12u320_fb_mark_dirty(pipe->plane.state->fb, &rect);
+
+	if (crtc->state->event) {
+		spin_lock_irq(&crtc->dev->event_lock);
+		drm_crtc_send_vblank_event(crtc, crtc->state->event);
+		crtc->state->event = NULL;
+		spin_unlock_irq(&crtc->dev->event_lock);
+	}
+}
+
+static const struct drm_simple_display_pipe_funcs gm12u320_pipe_funcs = {
+	.enable	    = gm12u320_pipe_enable,
+	.disable    = gm12u320_pipe_disable,
+	.update	    = gm12u320_pipe_update,
+};
+
+static const uint32_t gm12u320_pipe_formats[] = {
+	DRM_FORMAT_XRGB8888,
+};
+
+static const uint64_t gm12u320_pipe_modifiers[] = {
+	DRM_FORMAT_MOD_LINEAR,
+	DRM_FORMAT_MOD_INVALID
+};
+
+static void gm12u320_driver_release(struct drm_device *dev)
+{
+	struct gm12u320_device *gm12u320 = dev->dev_private;
+
+	gm12u320_usb_free(gm12u320);
+	drm_mode_config_cleanup(dev);
+	drm_dev_fini(dev);
+	kfree(gm12u320);
+}
+
+DEFINE_DRM_GEM_SHMEM_FOPS(gm12u320_fops);
+
+static struct drm_driver gm12u320_drm_driver = {
+	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
+
+	.name		 = DRIVER_NAME,
+	.desc		 = DRIVER_DESC,
+	.date		 = DRIVER_DATE,
+	.major		 = DRIVER_MAJOR,
+	.minor		 = DRIVER_MINOR,
+
+	.release	 = gm12u320_driver_release,
+	.fops		 = &gm12u320_fops,
+	DRM_GEM_SHMEM_DRIVER_OPS,
+};
+
+static const struct drm_mode_config_funcs gm12u320_mode_config_funcs = {
+	.fb_create = drm_gem_fb_create_with_dirty,
+	.atomic_check = drm_atomic_helper_check,
+	.atomic_commit = drm_atomic_helper_commit,
+};
+
+static int gm12u320_usb_probe(struct usb_interface *interface,
+			      const struct usb_device_id *id)
+{
+	struct gm12u320_device *gm12u320;
+	struct drm_device *dev;
+	int ret;
+
+	/*
+	 * The gm12u320 presents itself to the system as 2 usb mass-storage
+	 * interfaces, we only care about / need the first one.
+	 */
+	if (interface->cur_altsetting->desc.bInterfaceNumber != 0)
+		return -ENODEV;
+
+	gm12u320 = kzalloc(sizeof(*gm12u320), GFP_KERNEL);
+	if (gm12u320 == NULL)
+		return -ENOMEM;
+
+	gm12u320->udev = interface_to_usbdev(interface);
+	INIT_WORK(&gm12u320->fb_update.work, gm12u320_fb_update_work);
+	mutex_init(&gm12u320->fb_update.lock);
+	init_waitqueue_head(&gm12u320->fb_update.waitq);
+
+	dev = &gm12u320->dev;
+	ret = drm_dev_init(dev, &gm12u320_drm_driver, &interface->dev);
+	if (ret) {
+		kfree(gm12u320);
+		return ret;
+	}
+	dev->dev_private = gm12u320;
+
+	drm_mode_config_init(dev);
+	dev->mode_config.min_width = GM12U320_USER_WIDTH;
+	dev->mode_config.max_width = GM12U320_USER_WIDTH;
+	dev->mode_config.min_height = GM12U320_HEIGHT;
+	dev->mode_config.max_height = GM12U320_HEIGHT;
+	dev->mode_config.funcs = &gm12u320_mode_config_funcs;
+
+	ret = gm12u320_usb_alloc(gm12u320);
+	if (ret)
+		goto err_put;
+
+	ret = gm12u320_set_ecomode(gm12u320);
+	if (ret)
+		goto err_put;
+
+	ret = gm12u320_conn_init(gm12u320);
+	if (ret)
+		goto err_put;
+
+	ret = drm_simple_display_pipe_init(&gm12u320->dev,
+					   &gm12u320->pipe,
+					   &gm12u320_pipe_funcs,
+					   gm12u320_pipe_formats,
+					   ARRAY_SIZE(gm12u320_pipe_formats),
+					   gm12u320_pipe_modifiers,
+					   &gm12u320->conn);
+	if (ret)
+		goto err_put;
+
+	drm_mode_config_reset(dev);
+
+	usb_set_intfdata(interface, dev);
+	ret = drm_dev_register(dev, 0);
+	if (ret)
+		goto err_put;
+
+	drm_fbdev_generic_setup(dev, dev->mode_config.preferred_depth);
+
+	return 0;
+
+err_put:
+	drm_dev_put(dev);
+	return ret;
+}
+
+static void gm12u320_usb_disconnect(struct usb_interface *interface)
+{
+	struct drm_device *dev = usb_get_intfdata(interface);
+	struct gm12u320_device *gm12u320 = dev->dev_private;
+
+	gm12u320_stop_fb_update(gm12u320);
+	drm_dev_unplug(dev);
+	drm_dev_put(dev);
+}
+
+#ifdef CONFIG_PM
+static int gm12u320_suspend(struct usb_interface *interface,
+			    pm_message_t message)
+{
+	struct drm_device *dev = usb_get_intfdata(interface);
+	struct gm12u320_device *gm12u320 = dev->dev_private;
+
+	if (gm12u320->pipe_enabled)
+		gm12u320_stop_fb_update(gm12u320);
+
+	return 0;
+}
+
+static int gm12u320_resume(struct usb_interface *interface)
+{
+	struct drm_device *dev = usb_get_intfdata(interface);
+	struct gm12u320_device *gm12u320 = dev->dev_private;
+
+	gm12u320_set_ecomode(gm12u320);
+	if (gm12u320->pipe_enabled)
+		gm12u320_start_fb_update(gm12u320);
+
+	return 0;
+}
+#endif
+
+static const struct usb_device_id id_table[] = {
+	{ USB_DEVICE(0x1de1, 0xc102) },
+	{},
+};
+MODULE_DEVICE_TABLE(usb, id_table);
+
+static struct usb_driver gm12u320_usb_driver = {
+	.name = "gm12u320",
+	.probe = gm12u320_usb_probe,
+	.disconnect = gm12u320_usb_disconnect,
+	.id_table = id_table,
+#ifdef CONFIG_PM
+	.suspend = gm12u320_suspend,
+	.resume = gm12u320_resume,
+	.reset_resume = gm12u320_resume,
+#endif
+};
+
+module_usb_driver(gm12u320_usb_driver);
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_LICENSE("GPL");