From acd45c56790a3b558b0b0081678a20b0a0d89b0f Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 4 Aug 2022 09:58:23 +0200
Subject: drm/udl: Replace semaphore with a simple wait queue

UDL driver uses a semaphore for controlling the emptiness of FIFO in a
slightly funky way.  This patch replaces it with a wait queue and
controls the emptiness with the standard wait_event*() macro instead,
which is a more straightforward implementation.

While we are at it, drop the dead code for delayed semaphore down,
too.

Tested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220804075826.27036-2-tiwai@suse.de
---
 drivers/gpu/drm/udl/udl_main.c | 84 ++++++++++++------------------------------
 1 file changed, 23 insertions(+), 61 deletions(-)

(limited to 'drivers/gpu/drm/udl/udl_main.c')

diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index 853f147036f6..67fd41e59b80 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -23,9 +23,6 @@
 #define WRITES_IN_FLIGHT (4)
 #define MAX_VENDOR_DESCRIPTOR_SIZE 256
 
-#define GET_URB_TIMEOUT	HZ
-#define FREE_URB_TIMEOUT (HZ*2)
-
 static int udl_parse_vendor_descriptor(struct udl_device *udl)
 {
 	struct usb_device *udev = udl_to_usb_device(udl);
@@ -119,14 +116,6 @@ static int udl_select_std_channel(struct udl_device *udl)
 	return ret < 0 ? ret : 0;
 }
 
-static void udl_release_urb_work(struct work_struct *work)
-{
-	struct urb_node *unode = container_of(work, struct urb_node,
-					      release_urb_work.work);
-
-	up(&unode->dev->urbs.limit_sem);
-}
-
 void udl_urb_completion(struct urb *urb)
 {
 	struct urb_node *unode = urb->context;
@@ -150,23 +139,13 @@ void udl_urb_completion(struct urb *urb)
 	udl->urbs.available++;
 	spin_unlock_irqrestore(&udl->urbs.lock, flags);
 
-#if 0
-	/*
-	 * When using fb_defio, we deadlock if up() is called
-	 * while another is waiting. So queue to another process.
-	 */
-	if (fb_defio)
-		schedule_delayed_work(&unode->release_urb_work, 0);
-	else
-#endif
-		up(&udl->urbs.limit_sem);
+	wake_up(&udl->urbs.sleep);
 }
 
 static void udl_free_urb_list(struct drm_device *dev)
 {
 	struct udl_device *udl = to_udl(dev);
 	int count = udl->urbs.count;
-	struct list_head *node;
 	struct urb_node *unode;
 	struct urb *urb;
 
@@ -174,23 +153,15 @@ static void udl_free_urb_list(struct drm_device *dev)
 
 	/* keep waiting and freeing, until we've got 'em all */
 	while (count--) {
-		down(&udl->urbs.limit_sem);
-
-		spin_lock_irq(&udl->urbs.lock);
-
-		node = udl->urbs.list.next; /* have reserved one with sem */
-		list_del_init(node);
-
-		spin_unlock_irq(&udl->urbs.lock);
-
-		unode = list_entry(node, struct urb_node, entry);
-		urb = unode->urb;
-
+		urb = udl_get_urb_timeout(dev, MAX_SCHEDULE_TIMEOUT);
+		if (WARN_ON(!urb))
+			break;
+		unode = urb->context;
 		/* Free each separately allocated piece */
 		usb_free_coherent(urb->dev, udl->urbs.size,
 				  urb->transfer_buffer, urb->transfer_dma);
 		usb_free_urb(urb);
-		kfree(node);
+		kfree(unode);
 	}
 	udl->urbs.count = 0;
 }
@@ -210,7 +181,7 @@ retry:
 	udl->urbs.size = size;
 	INIT_LIST_HEAD(&udl->urbs.list);
 
-	sema_init(&udl->urbs.limit_sem, 0);
+	init_waitqueue_head(&udl->urbs.sleep);
 	udl->urbs.count = 0;
 	udl->urbs.available = 0;
 
@@ -220,9 +191,6 @@ retry:
 			break;
 		unode->dev = udl;
 
-		INIT_DELAYED_WORK(&unode->release_urb_work,
-			  udl_release_urb_work);
-
 		urb = usb_alloc_urb(0, GFP_KERNEL);
 		if (!urb) {
 			kfree(unode);
@@ -250,7 +218,6 @@ retry:
 
 		list_add_tail(&unode->entry, &udl->urbs.list);
 
-		up(&udl->urbs.limit_sem);
 		udl->urbs.count++;
 		udl->urbs.available++;
 	}
@@ -260,36 +227,31 @@ retry:
 	return udl->urbs.count;
 }
 
-struct urb *udl_get_urb(struct drm_device *dev)
+struct urb *udl_get_urb_timeout(struct drm_device *dev, long timeout)
 {
 	struct udl_device *udl = to_udl(dev);
-	int ret = 0;
-	struct list_head *entry;
-	struct urb_node *unode;
-	struct urb *urb = NULL;
+	struct urb_node *unode = NULL;
 
-	/* Wait for an in-flight buffer to complete and get re-queued */
-	ret = down_timeout(&udl->urbs.limit_sem, GET_URB_TIMEOUT);
-	if (ret) {
-		DRM_INFO("wait for urb interrupted: %x available: %d\n",
-		       ret, udl->urbs.available);
-		goto error;
-	}
+	if (!udl->urbs.count)
+		return NULL;
 
+	/* Wait for an in-flight buffer to complete and get re-queued */
 	spin_lock_irq(&udl->urbs.lock);
+	if (!wait_event_lock_irq_timeout(udl->urbs.sleep,
+					 !list_empty(&udl->urbs.list),
+					 udl->urbs.lock, timeout)) {
+		DRM_INFO("wait for urb interrupted: available: %d\n",
+			 udl->urbs.available);
+		goto unlock;
+	}
 
-	BUG_ON(list_empty(&udl->urbs.list)); /* reserved one with limit_sem */
-	entry = udl->urbs.list.next;
-	list_del_init(entry);
+	unode = list_first_entry(&udl->urbs.list, struct urb_node, entry);
+	list_del_init(&unode->entry);
 	udl->urbs.available--;
 
+unlock:
 	spin_unlock_irq(&udl->urbs.lock);
-
-	unode = list_entry(entry, struct urb_node, entry);
-	urb = unode->urb;
-
-error:
-	return urb;
+	return unode ? unode->urb : NULL;
 }
 
 int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len)
-- 
cgit v1.2.3-59-g8ed1b


From 0f7dc324b2e9e55db9323302f944fd952dbed967 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 4 Aug 2022 09:58:24 +0200
Subject: drm/udl: Sync pending URBs at suspend / disconnect

We need to wait for finishing to process the all URBs after disabling
the pipe; otherwise pending URBs may stray at suspend/resume, leading
to a possible memory corruption in a worst case.

Tested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220804075826.27036-3-tiwai@suse.de
---
 drivers/gpu/drm/udl/udl_drv.h     |  1 +
 drivers/gpu/drm/udl/udl_main.c    | 17 +++++++++++++++++
 drivers/gpu/drm/udl/udl_modeset.c |  2 ++
 3 files changed, 20 insertions(+)

(limited to 'drivers/gpu/drm/udl/udl_main.c')

diff --git a/drivers/gpu/drm/udl/udl_drv.h b/drivers/gpu/drm/udl/udl_drv.h
index e008686ec738..f01e50c5b7b7 100644
--- a/drivers/gpu/drm/udl/udl_drv.h
+++ b/drivers/gpu/drm/udl/udl_drv.h
@@ -83,6 +83,7 @@ static inline struct urb *udl_get_urb(struct drm_device *dev)
 }
 
 int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len);
+int udl_sync_pending_urbs(struct drm_device *dev);
 void udl_urb_completion(struct urb *urb);
 
 int udl_init(struct udl_device *udl);
diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index 67fd41e59b80..93615648414b 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -270,6 +270,23 @@ int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len)
 	return ret;
 }
 
+/* wait until all pending URBs have been processed */
+int udl_sync_pending_urbs(struct drm_device *dev)
+{
+	struct udl_device *udl = to_udl(dev);
+	int ret = 0;
+
+	spin_lock_irq(&udl->urbs.lock);
+	/* 2 seconds as a sane timeout */
+	if (!wait_event_lock_irq_timeout(udl->urbs.sleep,
+					 udl->urbs.available == udl->urbs.count,
+					 udl->urbs.lock,
+					 msecs_to_jiffies(2000)))
+		ret = -ETIMEDOUT;
+	spin_unlock_irq(&udl->urbs.lock);
+	return ret;
+}
+
 int udl_init(struct udl_device *udl)
 {
 	struct drm_device *dev = &udl->drm;
diff --git a/drivers/gpu/drm/udl/udl_modeset.c b/drivers/gpu/drm/udl/udl_modeset.c
index e67c40a48fb4..50025606b6ad 100644
--- a/drivers/gpu/drm/udl/udl_modeset.c
+++ b/drivers/gpu/drm/udl/udl_modeset.c
@@ -408,6 +408,8 @@ udl_simple_display_pipe_disable(struct drm_simple_display_pipe *pipe)
 	buf = udl_dummy_render(buf);
 
 	udl_submit_urb(dev, urb, buf - (char *)urb->transfer_buffer);
+
+	udl_sync_pending_urbs(dev);
 }
 
 static void
-- 
cgit v1.2.3-59-g8ed1b


From e25d5954264d1871ab2792c7ca2298b811462500 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 4 Aug 2022 09:58:25 +0200
Subject: drm/udl: Kill pending URBs at suspend and disconnect

At both suspend and disconnect, we should rather cancel the pending
URBs immediately.  For the suspend case, the display will be turned
off, so it makes no sense to process the rendering.  And for the
disconnect case, the device may be no longer accessible, hence we
shouldn't do any submission.

Tested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220804075826.27036-4-tiwai@suse.de
---
 drivers/gpu/drm/udl/udl_drv.h     |  2 ++
 drivers/gpu/drm/udl/udl_main.c    | 25 ++++++++++++++++++++++---
 drivers/gpu/drm/udl/udl_modeset.c |  2 ++
 3 files changed, 26 insertions(+), 3 deletions(-)

(limited to 'drivers/gpu/drm/udl/udl_main.c')

diff --git a/drivers/gpu/drm/udl/udl_drv.h b/drivers/gpu/drm/udl/udl_drv.h
index f01e50c5b7b7..28aaf75d71cf 100644
--- a/drivers/gpu/drm/udl/udl_drv.h
+++ b/drivers/gpu/drm/udl/udl_drv.h
@@ -39,6 +39,7 @@ struct urb_node {
 
 struct urb_list {
 	struct list_head list;
+	struct list_head in_flight;
 	spinlock_t lock;
 	wait_queue_head_t sleep;
 	int available;
@@ -84,6 +85,7 @@ static inline struct urb *udl_get_urb(struct drm_device *dev)
 
 int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len);
 int udl_sync_pending_urbs(struct drm_device *dev);
+void udl_kill_pending_urbs(struct drm_device *dev);
 void udl_urb_completion(struct urb *urb);
 
 int udl_init(struct udl_device *udl);
diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index 93615648414b..47204b7eb10e 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -135,7 +135,7 @@ void udl_urb_completion(struct urb *urb)
 	urb->transfer_buffer_length = udl->urbs.size; /* reset to actual */
 
 	spin_lock_irqsave(&udl->urbs.lock, flags);
-	list_add_tail(&unode->entry, &udl->urbs.list);
+	list_move(&unode->entry, &udl->urbs.list);
 	udl->urbs.available++;
 	spin_unlock_irqrestore(&udl->urbs.lock, flags);
 
@@ -180,6 +180,7 @@ static int udl_alloc_urb_list(struct drm_device *dev, int count, size_t size)
 retry:
 	udl->urbs.size = size;
 	INIT_LIST_HEAD(&udl->urbs.list);
+	INIT_LIST_HEAD(&udl->urbs.in_flight);
 
 	init_waitqueue_head(&udl->urbs.sleep);
 	udl->urbs.count = 0;
@@ -246,7 +247,7 @@ struct urb *udl_get_urb_timeout(struct drm_device *dev, long timeout)
 	}
 
 	unode = list_first_entry(&udl->urbs.list, struct urb_node, entry);
-	list_del_init(&unode->entry);
+	list_move(&unode->entry, &udl->urbs.in_flight);
 	udl->urbs.available--;
 
 unlock:
@@ -279,7 +280,7 @@ int udl_sync_pending_urbs(struct drm_device *dev)
 	spin_lock_irq(&udl->urbs.lock);
 	/* 2 seconds as a sane timeout */
 	if (!wait_event_lock_irq_timeout(udl->urbs.sleep,
-					 udl->urbs.available == udl->urbs.count,
+					 list_empty(&udl->urbs.in_flight),
 					 udl->urbs.lock,
 					 msecs_to_jiffies(2000)))
 		ret = -ETIMEDOUT;
@@ -287,6 +288,23 @@ int udl_sync_pending_urbs(struct drm_device *dev)
 	return ret;
 }
 
+/* kill pending URBs */
+void udl_kill_pending_urbs(struct drm_device *dev)
+{
+	struct udl_device *udl = to_udl(dev);
+	struct urb_node *unode;
+
+	spin_lock_irq(&udl->urbs.lock);
+	while (!list_empty(&udl->urbs.in_flight)) {
+		unode = list_first_entry(&udl->urbs.in_flight,
+					 struct urb_node, entry);
+		spin_unlock_irq(&udl->urbs.lock);
+		usb_kill_urb(unode->urb);
+		spin_lock_irq(&udl->urbs.lock);
+	}
+	spin_unlock_irq(&udl->urbs.lock);
+}
+
 int udl_init(struct udl_device *udl)
 {
 	struct drm_device *dev = &udl->drm;
@@ -335,6 +353,7 @@ int udl_drop_usb(struct drm_device *dev)
 {
 	struct udl_device *udl = to_udl(dev);
 
+	udl_kill_pending_urbs(dev);
 	udl_free_urb_list(dev);
 	put_device(udl->dmadev);
 	udl->dmadev = NULL;
diff --git a/drivers/gpu/drm/udl/udl_modeset.c b/drivers/gpu/drm/udl/udl_modeset.c
index 50025606b6ad..169110d8fc2e 100644
--- a/drivers/gpu/drm/udl/udl_modeset.c
+++ b/drivers/gpu/drm/udl/udl_modeset.c
@@ -397,6 +397,8 @@ udl_simple_display_pipe_disable(struct drm_simple_display_pipe *pipe)
 	struct urb *urb;
 	char *buf;
 
+	udl_kill_pending_urbs(dev);
+
 	urb = udl_get_urb(dev);
 	if (!urb)
 		return;
-- 
cgit v1.2.3-59-g8ed1b


From 7350b2a3fbc6956b2b2234f6d27d030c70b451bb Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 4 Aug 2022 09:58:26 +0200
Subject: drm/udl: Replace BUG_ON() with WARN_ON()

BUG_ON() is a tasteless choice as a sanity check for a driver like UDL
that isn't really a core code.  Replace with WARN_ON() and proper
error handling instead.

Tested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220804075826.27036-5-tiwai@suse.de
---
 drivers/gpu/drm/udl/udl_main.c     | 3 ++-
 drivers/gpu/drm/udl/udl_transfer.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

(limited to 'drivers/gpu/drm/udl/udl_main.c')

diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index 47204b7eb10e..fdafbf8f3c3c 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -260,7 +260,8 @@ int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len)
 	struct udl_device *udl = to_udl(dev);
 	int ret;
 
-	BUG_ON(len > udl->urbs.size);
+	if (WARN_ON(len > udl->urbs.size))
+		return -EINVAL;
 
 	urb->transfer_buffer_length = len; /* set to actual payload len */
 	ret = usb_submit_urb(urb, GFP_ATOMIC);
diff --git a/drivers/gpu/drm/udl/udl_transfer.c b/drivers/gpu/drm/udl/udl_transfer.c
index 971927669d6b..176ef2a6a731 100644
--- a/drivers/gpu/drm/udl/udl_transfer.c
+++ b/drivers/gpu/drm/udl/udl_transfer.c
@@ -220,7 +220,8 @@ int udl_render_hline(struct drm_device *dev, int log_bpp, struct urb **urb_ptr,
 	u8 *cmd = *urb_buf_ptr;
 	u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
 
-	BUG_ON(!(log_bpp == 1 || log_bpp == 2));
+	if (WARN_ON(!(log_bpp == 1 || log_bpp == 2)))
+		return -EINVAL;
 
 	line_start = (u8 *) (front + byte_offset);
 	next_pixel = line_start;
-- 
cgit v1.2.3-59-g8ed1b


From 1ceef996c99f1e8a44df8714fcf12822353ac488 Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: Thu, 8 Sep 2022 11:51:05 +0200
Subject: drm/udl: Add reset_resume

Implement the reset_resume callback of struct usb_driver. Set the
standard channel when called.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220908095115.23396-3-tiwai@suse.de
---
 drivers/gpu/drm/udl/udl_drv.c  | 11 +++++++++++
 drivers/gpu/drm/udl/udl_drv.h  |  1 +
 drivers/gpu/drm/udl/udl_main.c |  2 +-
 3 files changed, 13 insertions(+), 1 deletion(-)

(limited to 'drivers/gpu/drm/udl/udl_main.c')

diff --git a/drivers/gpu/drm/udl/udl_drv.c b/drivers/gpu/drm/udl/udl_drv.c
index 5703277c6f52..0ba88e5472a9 100644
--- a/drivers/gpu/drm/udl/udl_drv.c
+++ b/drivers/gpu/drm/udl/udl_drv.c
@@ -32,6 +32,16 @@ static int udl_usb_resume(struct usb_interface *interface)
 	return drm_mode_config_helper_resume(dev);
 }
 
+static int udl_usb_reset_resume(struct usb_interface *interface)
+{
+	struct drm_device *dev = usb_get_intfdata(interface);
+	struct udl_device *udl = to_udl(dev);
+
+	udl_select_std_channel(udl);
+
+	return drm_mode_config_helper_resume(dev);
+}
+
 /*
  * FIXME: Dma-buf sharing requires DMA support by the importing device.
  *        This function is a workaround to make USB devices work as well.
@@ -140,6 +150,7 @@ static struct usb_driver udl_driver = {
 	.disconnect = udl_usb_disconnect,
 	.suspend = udl_usb_suspend,
 	.resume = udl_usb_resume,
+	.reset_resume = udl_usb_reset_resume,
 	.id_table = id_table,
 };
 module_usb_driver(udl_driver);
diff --git a/drivers/gpu/drm/udl/udl_drv.h b/drivers/gpu/drm/udl/udl_drv.h
index 28aaf75d71cf..37c14b0ff1fc 100644
--- a/drivers/gpu/drm/udl/udl_drv.h
+++ b/drivers/gpu/drm/udl/udl_drv.h
@@ -95,6 +95,7 @@ int udl_render_hline(struct drm_device *dev, int log_bpp, struct urb **urb_ptr,
 		     u32 byte_offset, u32 device_byte_offset, u32 byte_width);
 
 int udl_drop_usb(struct drm_device *dev);
+int udl_select_std_channel(struct udl_device *udl);
 
 #define CMD_WRITE_RAW8   "\xAF\x60" /**< 8 bit raw write command. */
 #define CMD_WRITE_RL8    "\xAF\x61" /**< 8 bit run length command. */
diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index fdafbf8f3c3c..7d1e6bbc165c 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -92,7 +92,7 @@ success:
 /*
  * Need to ensure a channel is selected before submitting URBs
  */
-static int udl_select_std_channel(struct udl_device *udl)
+int udl_select_std_channel(struct udl_device *udl)
 {
 	static const u8 set_def_chn[] = {0x57, 0xCD, 0xDC, 0xA7,
 					 0x1C, 0x88, 0x5E, 0x15,
-- 
cgit v1.2.3-59-g8ed1b


From ed9605a66b62f27513aba1d95f7d470c4abda29f Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 8 Sep 2022 11:51:07 +0200
Subject: Revert "drm/udl: Kill pending URBs at suspend and disconnect"

This reverts the recent fix commit
  e25d5954264d ("drm/udl: Kill pending URBs at suspend and disconnect")
as it turned out to lead to potential hangup at a disconnection, and
it doesn't help much for suspend/resume problem, either.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220908095115.23396-5-tiwai@suse.de
---
 drivers/gpu/drm/udl/udl_drv.h     |  2 --
 drivers/gpu/drm/udl/udl_main.c    | 25 +++----------------------
 drivers/gpu/drm/udl/udl_modeset.c |  2 --
 3 files changed, 3 insertions(+), 26 deletions(-)

(limited to 'drivers/gpu/drm/udl/udl_main.c')

diff --git a/drivers/gpu/drm/udl/udl_drv.h b/drivers/gpu/drm/udl/udl_drv.h
index 37c14b0ff1fc..5923d2e02bc8 100644
--- a/drivers/gpu/drm/udl/udl_drv.h
+++ b/drivers/gpu/drm/udl/udl_drv.h
@@ -39,7 +39,6 @@ struct urb_node {
 
 struct urb_list {
 	struct list_head list;
-	struct list_head in_flight;
 	spinlock_t lock;
 	wait_queue_head_t sleep;
 	int available;
@@ -85,7 +84,6 @@ static inline struct urb *udl_get_urb(struct drm_device *dev)
 
 int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len);
 int udl_sync_pending_urbs(struct drm_device *dev);
-void udl_kill_pending_urbs(struct drm_device *dev);
 void udl_urb_completion(struct urb *urb);
 
 int udl_init(struct udl_device *udl);
diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index 7d1e6bbc165c..a9f6b710b254 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -135,7 +135,7 @@ void udl_urb_completion(struct urb *urb)
 	urb->transfer_buffer_length = udl->urbs.size; /* reset to actual */
 
 	spin_lock_irqsave(&udl->urbs.lock, flags);
-	list_move(&unode->entry, &udl->urbs.list);
+	list_add_tail(&unode->entry, &udl->urbs.list);
 	udl->urbs.available++;
 	spin_unlock_irqrestore(&udl->urbs.lock, flags);
 
@@ -180,7 +180,6 @@ static int udl_alloc_urb_list(struct drm_device *dev, int count, size_t size)
 retry:
 	udl->urbs.size = size;
 	INIT_LIST_HEAD(&udl->urbs.list);
-	INIT_LIST_HEAD(&udl->urbs.in_flight);
 
 	init_waitqueue_head(&udl->urbs.sleep);
 	udl->urbs.count = 0;
@@ -247,7 +246,7 @@ struct urb *udl_get_urb_timeout(struct drm_device *dev, long timeout)
 	}
 
 	unode = list_first_entry(&udl->urbs.list, struct urb_node, entry);
-	list_move(&unode->entry, &udl->urbs.in_flight);
+	list_del_init(&unode->entry);
 	udl->urbs.available--;
 
 unlock:
@@ -281,7 +280,7 @@ int udl_sync_pending_urbs(struct drm_device *dev)
 	spin_lock_irq(&udl->urbs.lock);
 	/* 2 seconds as a sane timeout */
 	if (!wait_event_lock_irq_timeout(udl->urbs.sleep,
-					 list_empty(&udl->urbs.in_flight),
+					 udl->urbs.available == udl->urbs.count,
 					 udl->urbs.lock,
 					 msecs_to_jiffies(2000)))
 		ret = -ETIMEDOUT;
@@ -289,23 +288,6 @@ int udl_sync_pending_urbs(struct drm_device *dev)
 	return ret;
 }
 
-/* kill pending URBs */
-void udl_kill_pending_urbs(struct drm_device *dev)
-{
-	struct udl_device *udl = to_udl(dev);
-	struct urb_node *unode;
-
-	spin_lock_irq(&udl->urbs.lock);
-	while (!list_empty(&udl->urbs.in_flight)) {
-		unode = list_first_entry(&udl->urbs.in_flight,
-					 struct urb_node, entry);
-		spin_unlock_irq(&udl->urbs.lock);
-		usb_kill_urb(unode->urb);
-		spin_lock_irq(&udl->urbs.lock);
-	}
-	spin_unlock_irq(&udl->urbs.lock);
-}
-
 int udl_init(struct udl_device *udl)
 {
 	struct drm_device *dev = &udl->drm;
@@ -354,7 +336,6 @@ int udl_drop_usb(struct drm_device *dev)
 {
 	struct udl_device *udl = to_udl(dev);
 
-	udl_kill_pending_urbs(dev);
 	udl_free_urb_list(dev);
 	put_device(udl->dmadev);
 	udl->dmadev = NULL;
diff --git a/drivers/gpu/drm/udl/udl_modeset.c b/drivers/gpu/drm/udl/udl_modeset.c
index b2377b706482..cbdda2d8b882 100644
--- a/drivers/gpu/drm/udl/udl_modeset.c
+++ b/drivers/gpu/drm/udl/udl_modeset.c
@@ -394,8 +394,6 @@ udl_simple_display_pipe_disable(struct drm_simple_display_pipe *pipe)
 	struct urb *urb;
 	char *buf;
 
-	udl_kill_pending_urbs(dev);
-
 	urb = udl_get_urb(dev);
 	if (!urb)
 		return;
-- 
cgit v1.2.3-59-g8ed1b


From 53593515ec1a4a5afaaa88fd4522bc4c2d7f5d9b Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 8 Sep 2022 11:51:08 +0200
Subject: drm/udl: Suppress error print for -EPROTO at URB completion

The driver may receive -EPROTO at the URB completion when the device
gets disconnected, and it's a normal situation.  Suppress the error
print for that, too.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220908095115.23396-6-tiwai@suse.de
---
 drivers/gpu/drm/udl/udl_main.c | 1 +
 1 file changed, 1 insertion(+)

(limited to 'drivers/gpu/drm/udl/udl_main.c')

diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index a9f6b710b254..6aed6e0f669c 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -126,6 +126,7 @@ void udl_urb_completion(struct urb *urb)
 	if (urb->status) {
 		if (!(urb->status == -ENOENT ||
 		    urb->status == -ECONNRESET ||
+		    urb->status == -EPROTO ||
 		    urb->status == -ESHUTDOWN)) {
 			DRM_ERROR("%s - nonzero write bulk status received: %d\n",
 				__func__, urb->status);
-- 
cgit v1.2.3-59-g8ed1b


From 2a07a5ddb135e4bd15bf6468b7d2daa4deeaf07d Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 8 Sep 2022 11:51:09 +0200
Subject: drm/udl: Increase the default URB list size to 20

It seems that the current size (4) for the URB list is too small on
some devices, and it resulted in the occasional stalls.  Increase the
default URB list size to 20 for working around it.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220908095115.23396-7-tiwai@suse.de
---
 drivers/gpu/drm/udl/udl_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'drivers/gpu/drm/udl/udl_main.c')

diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index 6aed6e0f669c..2b7eafd48ec2 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -20,7 +20,7 @@
 #define NR_USB_REQUEST_CHANNEL 0x12
 
 #define MAX_TRANSFER (PAGE_SIZE*16 - BULK_SIZE)
-#define WRITES_IN_FLIGHT (4)
+#define WRITES_IN_FLIGHT (20)
 #define MAX_VENDOR_DESCRIPTOR_SIZE 256
 
 static int udl_parse_vendor_descriptor(struct udl_device *udl)
-- 
cgit v1.2.3-59-g8ed1b


From 046f4f0af7fd1fad06793d863d288c6b2cd84e99 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 8 Sep 2022 11:51:12 +0200
Subject: drm/udl: Fix potential URB leaks

A couple of error handlings forgot to process the URB completion.
Those are both with WARN_ON() so should be visible, but we must fix
them in anyway.

Fixes: 7350b2a3fbc6 ("drm/udl: Replace BUG_ON() with WARN_ON()")
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220908095115.23396-10-tiwai@suse.de
---
 drivers/gpu/drm/udl/udl_main.c     | 8 +++++---
 drivers/gpu/drm/udl/udl_transfer.c | 5 ++++-
 2 files changed, 9 insertions(+), 4 deletions(-)

(limited to 'drivers/gpu/drm/udl/udl_main.c')

diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index 2b7eafd48ec2..de28eeff3155 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -260,11 +260,13 @@ int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len)
 	struct udl_device *udl = to_udl(dev);
 	int ret;
 
-	if (WARN_ON(len > udl->urbs.size))
-		return -EINVAL;
-
+	if (WARN_ON(len > udl->urbs.size)) {
+		ret = -EINVAL;
+		goto error;
+	}
 	urb->transfer_buffer_length = len; /* set to actual payload len */
 	ret = usb_submit_urb(urb, GFP_ATOMIC);
+ error:
 	if (ret) {
 		udl_urb_completion(urb); /* because no one else will */
 		DRM_ERROR("usb_submit_urb error %x\n", ret);
diff --git a/drivers/gpu/drm/udl/udl_transfer.c b/drivers/gpu/drm/udl/udl_transfer.c
index a431208dda85..b57844632dbd 100644
--- a/drivers/gpu/drm/udl/udl_transfer.c
+++ b/drivers/gpu/drm/udl/udl_transfer.c
@@ -180,8 +180,11 @@ int udl_render_hline(struct drm_device *dev, int log_bpp, struct urb **urb_ptr,
 	u8 *cmd = *urb_buf_ptr;
 	u8 *cmd_end = (u8 *) urb->transfer_buffer + urb->transfer_buffer_length;
 
-	if (WARN_ON(!(log_bpp == 1 || log_bpp == 2)))
+	if (WARN_ON(!(log_bpp == 1 || log_bpp == 2))) {
+		/* need to finish URB at error from this function */
+		udl_urb_completion(urb);
 		return -EINVAL;
+	}
 
 	line_start = (u8 *) (front + byte_offset);
 	next_pixel = line_start;
-- 
cgit v1.2.3-59-g8ed1b


From c5c354a3a4728045e1342166394c615d75d45377 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 8 Sep 2022 11:51:13 +0200
Subject: drm/udl: Fix inconsistent urbs.count value during udl_free_urb_list()

In the current design, udl_get_urb() may be called asynchronously
during the driver freeing its URL list via udl_free_urb_list().
The problem is that the sync is determined by comparing the urbs.count
and urbs.available fields, while we clear urbs.count field only once
after udl_free_urb_list() finishes, i.e. during udl_free_urb_list(),
the state becomes inconsistent.

For fixing this inconsistency and also for hardening the locking
scheme, this patch does a slight refactoring of the code around
udl_get_urb() and udl_free_urb_list().  Now urbs.count is updated in
the same spinlock at extracting a URB from the list in
udl_free_url_list().

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220908095115.23396-11-tiwai@suse.de
---
 drivers/gpu/drm/udl/udl_drv.h  |  8 +-------
 drivers/gpu/drm/udl/udl_main.c | 42 +++++++++++++++++++++++++++++-------------
 2 files changed, 30 insertions(+), 20 deletions(-)

(limited to 'drivers/gpu/drm/udl/udl_main.c')

diff --git a/drivers/gpu/drm/udl/udl_drv.h b/drivers/gpu/drm/udl/udl_drv.h
index 5923d2e02bc8..d943684b5bbb 100644
--- a/drivers/gpu/drm/udl/udl_drv.h
+++ b/drivers/gpu/drm/udl/udl_drv.h
@@ -74,13 +74,7 @@ static inline struct usb_device *udl_to_usb_device(struct udl_device *udl)
 int udl_modeset_init(struct drm_device *dev);
 struct drm_connector *udl_connector_init(struct drm_device *dev);
 
-struct urb *udl_get_urb_timeout(struct drm_device *dev, long timeout);
-
-#define GET_URB_TIMEOUT	HZ
-static inline struct urb *udl_get_urb(struct drm_device *dev)
-{
-	return udl_get_urb_timeout(dev, GET_URB_TIMEOUT);
-}
+struct urb *udl_get_urb(struct drm_device *dev);
 
 int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len);
 int udl_sync_pending_urbs(struct drm_device *dev);
diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index de28eeff3155..16aa4a655e7f 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -23,6 +23,8 @@
 #define WRITES_IN_FLIGHT (20)
 #define MAX_VENDOR_DESCRIPTOR_SIZE 256
 
+static struct urb *udl_get_urb_locked(struct udl_device *udl, long timeout);
+
 static int udl_parse_vendor_descriptor(struct udl_device *udl)
 {
 	struct usb_device *udev = udl_to_usb_device(udl);
@@ -146,15 +148,17 @@ void udl_urb_completion(struct urb *urb)
 static void udl_free_urb_list(struct drm_device *dev)
 {
 	struct udl_device *udl = to_udl(dev);
-	int count = udl->urbs.count;
 	struct urb_node *unode;
 	struct urb *urb;
 
 	DRM_DEBUG("Waiting for completes and freeing all render urbs\n");
 
 	/* keep waiting and freeing, until we've got 'em all */
-	while (count--) {
-		urb = udl_get_urb_timeout(dev, MAX_SCHEDULE_TIMEOUT);
+	while (udl->urbs.count) {
+		spin_lock_irq(&udl->urbs.lock);
+		urb = udl_get_urb_locked(udl, MAX_SCHEDULE_TIMEOUT);
+		udl->urbs.count--;
+		spin_unlock_irq(&udl->urbs.lock);
 		if (WARN_ON(!urb))
 			break;
 		unode = urb->context;
@@ -164,7 +168,8 @@ static void udl_free_urb_list(struct drm_device *dev)
 		usb_free_urb(urb);
 		kfree(unode);
 	}
-	udl->urbs.count = 0;
+
+	wake_up_all(&udl->urbs.sleep);
 }
 
 static int udl_alloc_urb_list(struct drm_device *dev, int count, size_t size)
@@ -228,33 +233,44 @@ retry:
 	return udl->urbs.count;
 }
 
-struct urb *udl_get_urb_timeout(struct drm_device *dev, long timeout)
+static struct urb *udl_get_urb_locked(struct udl_device *udl, long timeout)
 {
-	struct udl_device *udl = to_udl(dev);
-	struct urb_node *unode = NULL;
+	struct urb_node *unode;
 
-	if (!udl->urbs.count)
-		return NULL;
+	assert_spin_locked(&udl->urbs.lock);
 
 	/* Wait for an in-flight buffer to complete and get re-queued */
-	spin_lock_irq(&udl->urbs.lock);
 	if (!wait_event_lock_irq_timeout(udl->urbs.sleep,
+					 !udl->urbs.count ||
 					 !list_empty(&udl->urbs.list),
 					 udl->urbs.lock, timeout)) {
 		DRM_INFO("wait for urb interrupted: available: %d\n",
 			 udl->urbs.available);
-		goto unlock;
+		return NULL;
 	}
 
+	if (!udl->urbs.count)
+		return NULL;
+
 	unode = list_first_entry(&udl->urbs.list, struct urb_node, entry);
 	list_del_init(&unode->entry);
 	udl->urbs.available--;
 
-unlock:
-	spin_unlock_irq(&udl->urbs.lock);
 	return unode ? unode->urb : NULL;
 }
 
+#define GET_URB_TIMEOUT	HZ
+struct urb *udl_get_urb(struct drm_device *dev)
+{
+	struct udl_device *udl = to_udl(dev);
+	struct urb *urb;
+
+	spin_lock_irq(&udl->urbs.lock);
+	urb = udl_get_urb_locked(udl, GET_URB_TIMEOUT);
+	spin_unlock_irq(&udl->urbs.lock);
+	return urb;
+}
+
 int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len)
 {
 	struct udl_device *udl = to_udl(dev);
-- 
cgit v1.2.3-59-g8ed1b


From 2c2705bd09730dba6017b26897a2bcd3c5d21557 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 8 Sep 2022 11:51:14 +0200
Subject: drm/udl: Don't re-initialize stuff at retrying the URB list
 allocation

udl_alloc_urb_list() retires the allocation if there is no enough room
left, and it reinitializes the stuff unnecessarily such as the linked
list head and the waitqueue, which could be harmful.  Those should be
outside the retry loop.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220908095115.23396-12-tiwai@suse.de
---
 drivers/gpu/drm/udl/udl_main.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

(limited to 'drivers/gpu/drm/udl/udl_main.c')

diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index 16aa4a655e7f..829edb60a987 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -182,15 +182,14 @@ static int udl_alloc_urb_list(struct drm_device *dev, int count, size_t size)
 	struct usb_device *udev = udl_to_usb_device(udl);
 
 	spin_lock_init(&udl->urbs.lock);
-
-retry:
-	udl->urbs.size = size;
 	INIT_LIST_HEAD(&udl->urbs.list);
-
 	init_waitqueue_head(&udl->urbs.sleep);
 	udl->urbs.count = 0;
 	udl->urbs.available = 0;
 
+retry:
+	udl->urbs.size = size;
+
 	while (udl->urbs.count * size < wanted_size) {
 		unode = kzalloc(sizeof(struct urb_node), GFP_KERNEL);
 		if (!unode)
-- 
cgit v1.2.3-59-g8ed1b


From fa47573b04a35078953be5f81a78f22c96358817 Mon Sep 17 00:00:00 2001
From: Takashi Iwai <tiwai@suse.de>
Date: Thu, 8 Sep 2022 11:51:15 +0200
Subject: drm/udl: Sync pending URBs at the end of suspend

It's better to perform the sync at the very last of the suspend
instead of the pipe-disable function, so that we can catch all pending
URBs (if any).

While we're at it, drop the error code from udl_sync_pending_urb()
since we basically ignore it; instead, give a clear error message
indicating a problem.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220908095115.23396-13-tiwai@suse.de
---
 drivers/gpu/drm/udl/udl_drv.c     | 8 +++++++-
 drivers/gpu/drm/udl/udl_drv.h     | 2 +-
 drivers/gpu/drm/udl/udl_main.c    | 6 ++----
 drivers/gpu/drm/udl/udl_modeset.c | 2 --
 4 files changed, 10 insertions(+), 8 deletions(-)

(limited to 'drivers/gpu/drm/udl/udl_main.c')

diff --git a/drivers/gpu/drm/udl/udl_drv.c b/drivers/gpu/drm/udl/udl_drv.c
index 0ba88e5472a9..91effdcefb6d 100644
--- a/drivers/gpu/drm/udl/udl_drv.c
+++ b/drivers/gpu/drm/udl/udl_drv.c
@@ -21,8 +21,14 @@ static int udl_usb_suspend(struct usb_interface *interface,
 			   pm_message_t message)
 {
 	struct drm_device *dev = usb_get_intfdata(interface);
+	int ret;
 
-	return drm_mode_config_helper_suspend(dev);
+	ret = drm_mode_config_helper_suspend(dev);
+	if (ret)
+		return ret;
+
+	udl_sync_pending_urbs(dev);
+	return 0;
 }
 
 static int udl_usb_resume(struct usb_interface *interface)
diff --git a/drivers/gpu/drm/udl/udl_drv.h b/drivers/gpu/drm/udl/udl_drv.h
index d943684b5bbb..b4cc7cc568c7 100644
--- a/drivers/gpu/drm/udl/udl_drv.h
+++ b/drivers/gpu/drm/udl/udl_drv.h
@@ -77,7 +77,7 @@ struct drm_connector *udl_connector_init(struct drm_device *dev);
 struct urb *udl_get_urb(struct drm_device *dev);
 
 int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len);
-int udl_sync_pending_urbs(struct drm_device *dev);
+void udl_sync_pending_urbs(struct drm_device *dev);
 void udl_urb_completion(struct urb *urb);
 
 int udl_init(struct udl_device *udl);
diff --git a/drivers/gpu/drm/udl/udl_main.c b/drivers/gpu/drm/udl/udl_main.c
index 829edb60a987..061cb88c08a2 100644
--- a/drivers/gpu/drm/udl/udl_main.c
+++ b/drivers/gpu/drm/udl/udl_main.c
@@ -290,10 +290,9 @@ int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len)
 }
 
 /* wait until all pending URBs have been processed */
-int udl_sync_pending_urbs(struct drm_device *dev)
+void udl_sync_pending_urbs(struct drm_device *dev)
 {
 	struct udl_device *udl = to_udl(dev);
-	int ret = 0;
 
 	spin_lock_irq(&udl->urbs.lock);
 	/* 2 seconds as a sane timeout */
@@ -301,9 +300,8 @@ int udl_sync_pending_urbs(struct drm_device *dev)
 					 udl->urbs.available == udl->urbs.count,
 					 udl->urbs.lock,
 					 msecs_to_jiffies(2000)))
-		ret = -ETIMEDOUT;
+		drm_err(dev, "Timeout for syncing pending URBs\n");
 	spin_unlock_irq(&udl->urbs.lock);
-	return ret;
 }
 
 int udl_init(struct udl_device *udl)
diff --git a/drivers/gpu/drm/udl/udl_modeset.c b/drivers/gpu/drm/udl/udl_modeset.c
index d5e20bf144bc..ec6876f449f3 100644
--- a/drivers/gpu/drm/udl/udl_modeset.c
+++ b/drivers/gpu/drm/udl/udl_modeset.c
@@ -377,8 +377,6 @@ udl_simple_display_pipe_disable(struct drm_simple_display_pipe *pipe)
 	buf = udl_dummy_render(buf);
 
 	udl_submit_urb(dev, urb, buf - (char *)urb->transfer_buffer);
-
-	udl_sync_pending_urbs(dev);
 }
 
 static void
-- 
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