On Mon, 2 Mar 2009 17:03:49 +0100, Jean Delvare wrote:
> As far as I can see the key difference between bttv-input and
> cx88-input is that bttv-input only uses a simple self-rearming timer,
> while cx88-input uses a timer and a separate workqueue. The timer runs
> the workqueue, which rearms the timer, etc. When you flush the timer,
> the separate workqueue can be still active. I presume this is what
> happens on my system. I guess the reason for the separate workqueue is
> that the processing may take some time and we don't want to hurt the
> system's performance?
>
> So we need to flush both the event workqueue (with
> flush_scheduled_work) and the separate workqueue (with
> flush_workqueue), at the same time, otherwise the active one may rearm
> the flushed one again. This looks tricky, as obviously we can't flush
> both at the exact same time. Alternatively, if we could get rid of one
> of the queues, we'd have only one that needs flushing, this would be a
> lot easier...
Switching to delayed_work seems to do the trick (note this is a 2.6.28
patch):
---
drivers/media/video/cx88/cx88-input.c | 26 ++++++++------------------
1 file changed, 8 insertions(+), 18 deletions(-)
--- linux-2.6.28.orig/drivers/media/video/cx88/cx88-input.c 2009-03-02
19:11:24.000000000 +0100
+++ linux-2.6.28/drivers/media/video/cx88/cx88-input.c 2009-03-02
19:49:31.000000000 +0100
@@ -48,8 +48,7 @@ struct cx88_IR {
/* poll external decoder */
int polling;
- struct work_struct work;
- struct timer_list timer;
+ struct delayed_work work;
u32 gpio_addr;
u32 last_gpio;
u32 mask_keycode;
@@ -143,27 +142,20 @@ static void cx88_ir_handle_key(struct cx
}
}
-static void ir_timer(unsigned long data)
-{
- struct cx88_IR *ir = (struct cx88_IR *)data;
-
- schedule_work(&ir->work);
-}
-
static void cx88_ir_work(struct work_struct *work)
{
- struct cx88_IR *ir = container_of(work, struct cx88_IR, work);
+ struct delayed_work *dwork = container_of(work, struct delayed_work,
work);
+ struct cx88_IR *ir = container_of(dwork, struct cx88_IR, work);
cx88_ir_handle_key(ir);
- mod_timer(&ir->timer, jiffies + msecs_to_jiffies(ir->polling));
+ schedule_delayed_work(dwork, msecs_to_jiffies(ir->polling));
}
void cx88_ir_start(struct cx88_core *core, struct cx88_IR *ir)
{
if (ir->polling) {
- setup_timer(&ir->timer, ir_timer, (unsigned long)ir);
- INIT_WORK(&ir->work, cx88_ir_work);
- schedule_work(&ir->work);
+ INIT_DELAYED_WORK(&ir->work, cx88_ir_work);
+ schedule_delayed_work(&ir->work, msecs_to_jiffies(ir->polling));
}
if (ir->sampling) {
core->pci_irqmask |= PCI_INT_IR_SMPINT;
@@ -179,10 +171,8 @@ void cx88_ir_stop(struct cx88_core *core
core->pci_irqmask &= ~PCI_INT_IR_SMPINT;
}
- if (ir->polling) {
- del_timer_sync(&ir->timer);
- flush_scheduled_work();
- }
+ if (ir->polling)
+ cancel_delayed_work_sync(&ir->work);
}
/* ---------------------------------------------------------------------- */
At least I didn't have any general protection fault with this patch
applied. Comments?
Thanks,
--
Jean Delvare
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