Hi Trilok,
On Thu, Jan 20, 2011 at 01:30:31PM +0530, Trilok Soni wrote:
> Hi Dmitry,
>
> On 1/20/2011 1:23 PM, Dmitry Torokhov wrote:
> > Hi Philippe,
> >
> > On Wed, Jan 12, 2011 at 10:41:32AM +0100, Philippe Langlais wrote:
> >> Signed-off-by: Philippe Langlais <philippe.langlais@xxxxxxxxxxxxxx>
> >> ---
> >> drivers/input/keyboard/gpio_keys.c | 6 +++---
> >> 1 files changed, 3 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c
> >> index 6069abe..eb30063 100644
> >> --- a/drivers/input/keyboard/gpio_keys.c
> >> +++ b/drivers/input/keyboard/gpio_keys.c
> >> @@ -322,7 +322,7 @@ static void gpio_keys_report_event(struct gpio_button_data *bdata)
> >> struct gpio_keys_button *button = bdata->button;
> >> struct input_dev *input = bdata->input;
> >> unsigned int type = button->type ?: EV_KEY;
> >> - int state = (gpio_get_value(button->gpio) ? 1 : 0) ^ button->active_low;
> >> + int state = (gpio_get_value_cansleep(button->gpio) ? 1 : 0) ^ button->active_low;
> >>
> >> input_event(input, type, button->code, !!state);
> >> input_sync(input);
> >> @@ -410,8 +410,8 @@ static int __devinit gpio_keys_setup_key(struct platform_device *pdev,
> >> if (!button->can_disable)
> >> irqflags |= IRQF_SHARED;
> >>
> >> - error = request_irq(irq, gpio_keys_isr, irqflags, desc, bdata);
> >> - if (error) {
> >> + error = request_any_context_irq(irq, gpio_keys_isr, irqflags, desc, bdata);
> >> + if (error < 0) {
> >
> > No, this it not correct. request_any_context_irq() means that you could
> > either get a hardirq or a treaded one. However above you are changing to
> > gpio_get_value_cansleep() which indicates that you can sleep.
> >
> > You need to either revert to gpio_get_value() or explicitly request
> > threaded IRQ.
>
> This could be problem. Say, we are doing request_any_context_irq(..) and gpio is over slow-bus,
> so we naturally get into the threaded code, and in the thread handler we are calling gpio_get_value(..),
> but in this case gpio_get_value could throw a warning that we should call gpio_get_value_cansleep(...)
> because sleep attribute is added into the gpiolib hook implementation for these gpios.
>
> Now suppose gpio is memory mapped and we enter into the hardirq and calling sleep variant into the
> handler code will be naturally bad.
>
> How about checking maysleep explicitly here while using the request_any_context_irq() call though
> the semantics of gpiolib framework discourages that.
>
Any drawbacks for explicitly switching to threaded IRQ and keeping
gpio_get_value_cansleep()? (That was the 2nd option I mentioned BTW).
--
Dmitry
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