The console functions are using spinlocks while calling fb-driver ops
but udlfb waits for a semaphore in many ops. This results in the BUG
"scheduling while atomic". One of those call flows is e.g.
vt_console_print() (spinlock printing_lock)
(...)
dlfb_ops_imageblit()
dlfb_handle_damage()
dlfb_get_urb()
down_timeout(semaphore)
BUG: scheduling while atomic
(...)
vt_console_print() (release spinlock printing_lock)
Fix this through a workqueue for dlfb_handle_damage().
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Alexander Holler <holler@xxxxxxxxxxxxx>
---
drivers/video/udlfb.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++-
include/video/udlfb.h | 1 +
2 files changed, 50 insertions(+), 1 deletion(-)
diff --git a/drivers/video/udlfb.c b/drivers/video/udlfb.c
index 86d449e..4a90784 100644
--- a/drivers/video/udlfb.c
+++ b/drivers/video/udlfb.c
@@ -569,7 +569,7 @@ static int dlfb_render_hline(struct dlfb_data *dev, struct urb **urb_ptr,
return 0;
}
-int dlfb_handle_damage(struct dlfb_data *dev, int x, int y,
+int dlfb_handle_damage_queued(struct dlfb_data *dev, int x, int y,
int width, int height, char *data)
{
int i, ret;
@@ -630,6 +630,44 @@ error:
return 0;
}
+struct dlfb_handle_damage_work {
+ struct work_struct my_work;
+ struct dlfb_data *dev;
+ char *data;
+ int x, y, width, height;
+};
+
+static void dlfb_handle_damage_work(struct work_struct *work)
+{
+ struct dlfb_handle_damage_work *my_work =
+ (struct dlfb_handle_damage_work *)work;
+
+ dlfb_handle_damage_queued(my_work->dev, my_work->x, my_work->y,
+ my_work->width, my_work->height, my_work->data);
+ kfree(work);
+ return;
+}
+
+void dlfb_handle_damage(struct dlfb_data *dev, int x, int y,
+ int width, int height, char *data)
+{
+ struct dlfb_handle_damage_work *work =
+ kmalloc(sizeof(struct dlfb_handle_damage_work), GFP_KERNEL);
+
+ if (!work) {
+ pr_err("unable to allocate work\n");
+ return;
+ }
+ INIT_WORK((struct work_struct *)work, dlfb_handle_damage_work);
+ work->dev = dev;
+ work->x = x;
+ work->y = y;
+ work->width = width;
+ work->height = height;
+ work->data = data;
+ queue_work(dev->handle_damage_wq, (struct work_struct *)work);
+}
+
/*
* Path triggered by usermode clients who write to filesystem
* e.g. cat filename > /dev/fb1
@@ -945,6 +983,9 @@ static void dlfb_free_framebuffer(struct dlfb_data *dev)
unregister_framebuffer(info);
+ if (dev->handle_damage_wq)
+ destroy_workqueue(dev->handle_damage_wq);
+
if (info->cmap.len != 0)
fb_dealloc_cmap(&info->cmap);
if (info->monspecs.modedb)
@@ -1694,6 +1735,13 @@ static void dlfb_init_framebuffer_work(struct work_struct *work)
goto error;
}
+ dev->handle_damage_wq = alloc_workqueue("udlfb_damage",
+ WQ_MEM_RECLAIM, 0);
+ if (dev->handle_damage_wq == NULL) {
+ pr_err("unable to allocate workqueue\n");
+ goto error;
+ }
+
/* ready to begin using device */
atomic_set(&dev->usb_active, 1);
diff --git a/include/video/udlfb.h b/include/video/udlfb.h
index f9466fa..1e765f9 100644
--- a/include/video/udlfb.h
+++ b/include/video/udlfb.h
@@ -43,6 +43,7 @@ struct dlfb_data {
bool virtualized; /* true when physical usb device not present */
struct delayed_work init_framebuffer_work;
struct delayed_work free_framebuffer_work;
+ struct workqueue_struct *handle_damage_wq;
atomic_t usb_active; /* 0 = update virtual buffer, but no usb traffic */
atomic_t lost_pixels; /* 1 = a render op failed. Need screen refresh */
char *edid; /* null until we read edid from hw or get from sysfs */
--
1.7.11.7
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