Hi,
On 10/3/20 12:45 AM, Coiby Xu wrote:
On Fri, Oct 02, 2020 at 09:44:54PM +0200, Hans de Goede wrote:
Hi,
On 10/2/20 4:51 PM, Coiby Xu wrote:
On Fri, Oct 02, 2020 at 03:36:29PM +0200, Hans de Goede wrote:
<snip>
So are you seeing these 7 interrupts / second for the touchpad irq or for
the GPIO controllers parent irq ?
Also to these 7 interrupts/sec stop happening when you do not touch the
touchpad ?
I see these 7 interrupts / second for the GPIO controller's parent irq.
And they stop happening when I don't touch the touchpad.
Only from the parent irq, or also on the touchpad irq itself ?
If this only happens on the parent irq, then I would start looking at the
amd-pinctrl code which determines which of its "child" irqs to fire.
This only happens on the parent irq. The input's pin#130 of the GIPO
chip is low most of the time and pin#130.
Right, but it is a low-level triggered IRQ, so when it is low it should
be executing the i2c-hid interrupt-handler. If it is not executing that
then it is time to look at amd-pinctrl's irq-handler and figure out why
that is not triggering the child irq handler for the touchpad.
I'm not sure if I have some incorrect understandings about GPIO
interrupt controller because I don't quite follow your reasoning.
What I actually suspect is there's something wrong with amd-pinctrl
which makes the GPIO chip fail to assert its common interrupt output
line connected to one IO-APIC's pin#7 thus IRQ#7 fails to fire. What
I learn about this low-level triggered IRQ is that the i2c-hid
interrupt-handler will be woken up by amd-pinctrl's irq-handler which
is executed when the parent IRQ#7 fires. The code path is as follows,
<IRQ>
dump_stack+0x64/0x88
__irq_wake_thread.cold+0x9/0x12
__handle_irq_event_percpu+0x80/0x1c0
handle_irq_event+0x58/0xb0
handle_level_irq+0xb7/0x1a0
generic_handle_irq+0x4a/0x60
amd_gpio_irq_handler+0x15f/0x1b0 [pinctrl_amd]
__handle_irq_event_percpu+0x45/0x1c0
handle_irq_event+0x58/0xb0
handle_fasteoi_irq+0xa2/0x210
do_IRQ+0x70/0x120
common_interrupt+0xf/0xf
</IRQ>
But the problem is somehow IRQ#7 doesn't even fire when the input's
pin#130 of the GIPO is low. Without IRQ#7 firing, amd-pinctrl's
irq-handler wouldn't be executed in the first place, let alone
triggering the child irq handler. Btw, amd-pinctrl's irq-handler
simply iterate over all pins. If there is mapped irq found for this
hwirq (yes, it won't even check if this pin triggers the interrupt),
then it will call generic_handle_irq. So there's nothing wrong about
this part of code.
Ok, so the i2c-hid irq does fire, but only 7 times a second just
like the GPIO controller's parent irq.
The only thing I can think of then is to add printk-s to check how
long the i2c-hid interrupt handler takes to complete. It could be
there is a subtle bug somewhere causing the i2c transfers to take
longer when run from a (threaded) irq handler. That would be weird
though, so I don't expect this to result in any useful findings.
Other then that I'm all out of ideas I'm afraid.
Regards,
Hans
