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authorDaniel Drake <drake@endlessm.com>2017-10-02 07:00:54 +0300
committerLinus Walleij <linus.walleij@linaro.org>2017-10-19 11:19:46 +0300
commit6afb10267c1692ada3a2903e31ea339917ad3ac0 (patch)
tree970990e77061622396c99efd2e8bcf1b15834556 /drivers/pinctrl
parent33d930e59a98fa10a0db9f56c7fa2f21a4aef9b9 (diff)
downloadlinux-6afb10267c1692ada3a2903e31ea339917ad3ac0.tar.xz
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 <drake@endlessm.com> Acked-by: Shah, Nehal-bakulchandra <Nehal-Bakulchandra.shah@amd.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'drivers/pinctrl')
-rw-r--r--drivers/pinctrl/pinctrl-amd.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/pinctrl/pinctrl-amd.c b/drivers/pinctrl/pinctrl-amd.c
index 3f6b34febbf1..433af328d981 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;
}
}