On 5/20/2024 04:38, Andy Shevchenko wrote:
On Sun, May 19, 2024 at 07:41:09AM -0500, Mario Limonciello wrote:
When a touchpad's attention interrupt is triggered on a different
CPU than the GPIO controller interrupt multiple CPUs wake up the system
and can cause higher power consumption than necessary for operating
the touchpad.
Waking up the additional CPUs is especially unnecessary as the
irq_ack() callback for pinctrl-amd doesn't do anything.
To solve this save the affinity of the GPIO controller interrupt when
it's set up and assign that affinity to the GPIO line IRQ.
I do not much care about AMD :-) case but I think this is quite a big hammer
with possible undesired effects. It will basically put _all_ GPIO IRQs on
the same CPU which may slow down other peripherals, like UART, with potential
of buffer overrun (on the high speed modes).
Yeah I see your point.
Ideally it should be done in a way that exact consumer may ask for this from
its driver. Yet, I have no idea how to achieve this, but it would be really
nice to have something in I²C HID to
set_the_same_affinity_as_parent/GPIO_irq()
You know I think this is only half of the problem. The interrupts need
to be aligned but so does the I2C traffic. This was something else that
Hans mentioned in the linked thread. It's a lot more complex to sync
everything up.
I'm tempted to have a helper that i2c-hid uses after everything is setup
to go and align the affinities rather than at probe.
...
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Hans de Goede <hdegoede@xxxxxxxxxx>
You can move these (Cc lines) to be after ---, that they won't pollute
the commit message with the same effect made on email, i.e. Cc'ing to
the listed people.
Right; thanks.
