diff options
author | Daniel Drake <drake@endlessm.com> | 2017-10-02 07:00:54 +0300 |
---|---|---|
committer | Linus Walleij <linus.walleij@linaro.org> | 2017-10-19 11:19:46 +0300 |
commit | 6afb10267c1692ada3a2903e31ea339917ad3ac0 (patch) | |
tree | 970990e77061622396c99efd2e8bcf1b15834556 /drivers/pinctrl | |
parent | 33d930e59a98fa10a0db9f56c7fa2f21a4aef9b9 (diff) | |
download | linux-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.c | 10 |
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; } } |