[PATCH] pinctrl: bcm2835: Clear the event latch register when disabling interrupts
jonathan at raspberrypi.org
Tue Jun 30 04:35:39 PDT 2015
It's possible to hit a race condition if interrupts are generated on a GPIO
pin when the IRQ line in question is being disabled.
If the interrupt is freed, bcm2835_gpio_irq_disable() is called which
disables the event generation sources (edge, level). If an event occurred
between the last disabling of hard IRQs and the write to the event
source registers, a bit would be set in the GPIO event detect register
(GPEDSn) which goes unacknowledged by bcm2835_gpio_irq_handler()
so Linux complains loudly.
There is no per-GPIO mask register, so when disabling GPIO interrupts
write 1 to the relevant bit in GPEDSn to clear out any stale events.
Signed-off-by: Jonathan Bell <jonathan at raspberrypi.org>
drivers/pinctrl/bcm/pinctrl-bcm2835.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/pinctrl/bcm/pinctrl-bcm2835.c b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
index efcf2a2..547b925 100644
@@ -473,6 +473,8 @@ static void bcm2835_gpio_irq_disable(struct irq_data *data)
bcm2835_gpio_irq_config(pc, gpio, false);
+ /* Clear events that were latched prior to clearing event sources */
+ bcm2835_gpio_set_bit(pc, GPEDS0, gpio);
More information about the linux-rpi-kernel