From 6afb10267c1692ada3a2903e31ea339917ad3ac0 Mon Sep 17 00:00:00 2001
From: Daniel Drake <drake@endlessm.com>
Date: Mon, 2 Oct 2017 12:00:54 +0800
Subject: [PATCH] pinctrl/amd: fix masking of GPIO interrupts
Git-commit: 6afb10267c1692ada3a2903e31ea339917ad3ac0
Patch-mainline: v4.14-rc7
References: bsc#1140463
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
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 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;
}
}
--
2.16.4