Arjan van de Ven wrote:
> On Wed, 2006-05-17 at 21:46 -0700, [email protected] wrote:
>
>>+
>>+#ifdef DEBUG
>>+#define debug(format, arg...) printk(KERN_DEBUG "ff-effects: " format "\n" , ## arg)
>>+#else
>>+#define debug(format, arg...) do {} while (0)
>>+#endif
>
>
> please just use the existing prdebug() thing for this, no need to invent
> your own ;)
Couldn't find any info on that one, are you sure you spelled it correctly?
>
>>+
>>+EXPORT_SYMBOL(input_ff_allocate);
>>+EXPORT_SYMBOL(input_ff_register);
>>+EXPORT_SYMBOL(input_ff_upload);
>>+EXPORT_SYMBOL(input_ff_erase);
>
>
> should these be _GPL exports?
>
Well, I don't know. When should EXPORT_SYMBOLs be EXPORT_SYMBOL_GPLs?
>
>>+
>>+#define spin_ff_cond_lock(_ff, _flags) \
>>+ do { \
>>+ if (!_ff->driver->playback) \
>>+ spin_lock_irqsave(&_ff->atomiclock, _flags); \
>>+ } while (0);
>>+
>>+#define spin_ff_cond_unlock(_ff, _flags) \
>>+ do { \
>>+ if (!_ff->driver->playback) \
>>+ spin_unlock_irqrestore(&_ff->atomiclock, _flags); \
>>+ } while (0);
>
>
>
> hmmm conditional locking like this always makes me very nervous... what
> is preventing ->playback from changing halfway a locked sequence?
Well, it's never changed, locked or not. But maybe we can get rid of
this condlocking alltogether, see my reply for Andrew Morton.
>
>>+ if (!events) {
>>+ debug("no actions");
>>+ del_timer(&ff->timer);
>
>
> are you really sure you don't need del_timer_sync() here?
>
Yes, this function is also called from inside the timer in question and
del_timer_sync() would block.
>
>
>>+static void input_ff_timer(unsigned long timer_data)
>>+{
>>+ struct input_dev *dev = (struct input_dev *) timer_data;
>>+ struct ff_device *ff = dev->ff;
>>+ struct ff_effect effect;
>>+ int i;
>>+ unsigned long flags;
>>+ int effects_pending;
>>+ unsigned long effect_handled[NBITS(FF_EFFECTS_MAX)];
>
>
>
> hmmm stack space?
>
I count 76 bytes (x86), is that too much?
>>+ } else {
>>+ ret = -ENOSYS;
>
>
> that is almost always a wrong return value
>
It's returned when the device is mem-capable but driver doesn't
implement set_gain() but sets FF_GAIN or when driver doesn't implement
set_autocenter() but sets FF_AUTOCENTER. But yes, if that happens, it's
a driver bug, so maybe this is not correct use for -ENOSYS. Probably
there should be BUG() too here.
>>+ if (test_bit(FF_CONSTANT, dev->ff->flags))
>>+ set_bit(FF_CONSTANT, dev->ffbit);
>>+ if (test_bit(FF_SPRING, dev->ff->flags))
>>+ set_bit(FF_SPRING, dev->ffbit);
>>+ if (test_bit(FF_FRICTION, dev->ff->flags))
>>+ set_bit(FF_FRICTION, dev->ffbit);
>>+ if (test_bit(FF_DAMPER, dev->ff->flags))
>>+ set_bit(FF_DAMPER, dev->ffbit);
>>+ if (test_bit(FF_INERTIA, dev->ff->flags))
>
>
> are you really sure you need atomic set_bit()'s here??
> if so.. I think you have a race ;)
Well, I'm not. Is there an alternative?
--
Anssi Hannula
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