From 6afb10267c1692ada3a2903e31ea339917ad3ac0 Mon Sep 17 00:00:00 2001 From: Daniel Drake Date: Mon, 2 Oct 2017 12:00:54 +0800 Subject: [PATCH] pinctrl/amd: fix masking of GPIO interrupts On Asus laptop models X505BA, X505BP, X542BA and X542BP, the i2c-hid touchpad (using a GPIO for interrupts) becomes unresponsive after a few minutes of usage, or after placing two fingers on the touchpad, which seems to have the effect of queuing up a large amount of input data to be transferred. When the touchpad is in unresponsive state, we observed that the GPIO level-triggered interrupt is still at it's active level, however the pinctrl-amd driver is not receiving/dispatching more interrupts at this point. After the initial interrupt arrives, amd_gpio_irq_mask() is called however we then see amd_gpio_irq_handler() being called repeatedly for the same irq; the interrupt mask is not taking effect because of the following sequence of events: - amd_gpio_irq_handler fires, reads and caches pin reg - amd_gpio_irq_handler calls generic_handle_irq() - During IRQ handling, amd_gpio_irq_mask() is called and modifies pin reg - amd_gpio_irq_handler clears interrupt by writing cached value The stale cached value written at the final stage undoes the masking. Fix this by re-reading the register before clearing the interrupt. I also spotted that the interrupt-clearing code can race against amd_gpio_irq_mask() / amd_gpio_irq_unmask(), so add locking there. Presumably this race was leading to the loss of interrupts. After these changes, the touchpad appears to be working fine. Signed-off-by: Daniel Drake Acked-by: Shah, Nehal-bakulchandra Signed-off-by: Linus Walleij --- drivers/pinctrl/pinctrl-amd.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c index 3f6b34f..433af32 100644 --- a/drivers/pinctrl/pinctrl-amd.c +++ b/drivers/pinctrl/pinctrl-amd.c @@ -534,8 +534,16 @@ static irqreturn_t amd_gpio_irq_handler(int irq, void *dev_id) continue; irq = irq_find_mapping(gc->irqdomain, irqnr + i); generic_handle_irq(irq); - /* Clear interrupt */ + + /* Clear interrupt. + * We must read the pin register again, in case the + * value was changed while executing + * generic_handle_irq() above. + */ + raw_spin_lock_irqsave(&gpio_dev->lock, flags); + regval = readl(regs + i); writel(regval, regs + i); + raw_spin_unlock_irqrestore(&gpio_dev->lock, flags); ret = IRQ_HANDLED; } } -- 2.7.4