From: Daniel Drake drake@endlessm.com
[ Upstream commit d21b8adbd475dba19ac2086d3306327b4a297418 ]
When cold-booting Asus X434DA, GPIO 7 is found to be already configured as an interrupt, and the GPIO level is found to be in a state that causes the interrupt to fire.
As soon as pinctrl-amd probes, this interrupt fires and invokes amd_gpio_irq_handler(). The IRQ is acked, but no GPIO-IRQ handler was invoked, so the GPIO level being unchanged just causes another interrupt to fire again immediately after.
This results in an interrupt storm causing this platform to hang during boot, right after pinctrl-amd is probed.
Detect this situation and disable the GPIO interrupt when this happens. This enables the affected platform to boot as normal. GPIO 7 actually is the I2C touchpad interrupt line, and later on, i2c-multitouch loads and re-enables this interrupt when it is ready to handle it.
Instead of this approach, I considered disabling all GPIO interrupts at probe time, however that seems a little risky, and I also confirmed that Windows does not seem to have this behaviour: the same 41 GPIO IRQs are enabled under both Linux and Windows, which is a far larger collection than the GPIOs referenced by the DSDT on this platform.
Signed-off-by: Daniel Drake drake@endlessm.com Link: https://lore.kernel.org/r/20190814090540.7152-1-drake@endlessm.com Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pinctrl/pinctrl-amd.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c index 1425c2874d402..cd7a5d95b499a 100644 --- a/drivers/pinctrl/pinctrl-amd.c +++ b/drivers/pinctrl/pinctrl-amd.c @@ -569,15 +569,25 @@ static irqreturn_t amd_gpio_irq_handler(int irq, void *dev_id) !(regval & BIT(INTERRUPT_MASK_OFF))) continue; irq = irq_find_mapping(gc->irq.domain, irqnr + i); - generic_handle_irq(irq); + if (irq != 0) + generic_handle_irq(irq);
/* Clear interrupt. * We must read the pin register again, in case the * value was changed while executing * generic_handle_irq() above. + * If we didn't find a mapping for the interrupt, + * disable it in order to avoid a system hang caused + * by an interrupt storm. */ raw_spin_lock_irqsave(&gpio_dev->lock, flags); regval = readl(regs + i); + if (irq == 0) { + regval &= ~BIT(INTERRUPT_ENABLE_OFF); + dev_dbg(&gpio_dev->pdev->dev, + "Disabling spurious GPIO IRQ %d\n", + irqnr + i); + } writel(regval, regs + i); raw_spin_unlock_irqrestore(&gpio_dev->lock, flags); ret = IRQ_HANDLED;