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: <sta...@vger.kernel.org>
Signed-off-by: Alexander Holler <hol...@ahsoftware.de>
---
drivers/video/udlfb.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 51 insertions(+), 2 deletions(-)
diff --git a/drivers/video/udlfb.c b/drivers/video/udlfb.c
index 86d449e..5aadcb2 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;
}
+static struct workqueue_struct *dlfb_handle_damage_wq;
+
+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) {
+ 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(dlfb_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 (dlfb_handle_damage_wq)
+ destroy_workqueue(dlfb_handle_damage_wq);
+
if (info->cmap.len != 0)
fb_dealloc_cmap(&info->cmap);
if (info->monspecs.modedb)
@@ -1626,13 +1667,13 @@ static int dlfb_usb_probe(struct usb_interface
*interface,
dev->sku_pixel_limit = pixel_limit;
}
-
if (!dlfb_alloc_urb_list(dev, WRITES_IN_FLIGHT, MAX_TRANSFER)) {
retval = -ENOMEM;
pr_err("dlfb_alloc_urb_list failed\n");
goto error;
}
+
kref_get(&dev->kref); /* matching kref_put in free_framebuffer_work */
/* We don't register a new USB class. Our client interface is fbdev */
@@ -1694,6 +1735,13 @@ static void dlfb_init_framebuffer_work(struct
work_struct *work)
goto error;
}
+ dlfb_handle_damage_wq = alloc_workqueue("udlfb_damage",
+ WQ_MEM_RECLAIM, 0);
+ if (dlfb_handle_damage_wq == NULL) {
+ pr_err("unable to allocate workqueue\n");
+ goto error;
+ }
+
/* ready to begin using device */
atomic_set(&dev->usb_active, 1);
@@ -1702,6 +1750,7 @@ static void dlfb_init_framebuffer_work(struct work_struct
*work)
dlfb_ops_check_var(&info->var, info);
dlfb_ops_set_par(info);
+
retval = register_framebuffer(info);
if (retval < 0) {
pr_err("register_framebuffer failed %d\n", retval);
--
1.7.11.7
--
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