Re: [PATCH RFC] mfd: intel-lpss: Set d3hot_delay to 0

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Fri, Oct 16, 2026 at 05:13:47PM +0530, Navon John Lukose wrote:
> intel-lpss-pci already clears d3cold_delay, but every runtime resume of an
> LPSS controller still sleeps the default 10 ms d3hot_delay in
> pci_power_up().
> 
> On Arrow Lake-H (Lenovo Yoga Pro 7 14IAH10) the delay costs 8-16 ms per
> resume of the touchpad's I2C controller, which lands on the first
> touchpad report after each 1 s autosuspend. With d3hot_delay set to 0 the
> power-up takes 64-256 us and the I2C transfers that follow complete
> without errors.

So, do you state that this patch fixes some bad touchpad behaviour? If so,
please, provide some logs.

> Commit 815b4448198f ("i3c: mipi-i3c-hci-pci: Set d3hot_delay to 0 for Intel
> controllers") does the same for the Intel I3C controllers.

Okay, it means they were tested.

...

> Notes:
>     RFC because I could only test Arrow Lake-H, and this applies to every LPSS
>     generation the driver handles, back to Sunrise Point. Andy, do any of the
>     older ones need the D3hot->D0 delay? If so I can limit it to newer IDs
>     through the driver data.

AFAIK 10 ms for D3hot delay is in accordance with PCI specification.
Yes, we use quirk_remove_d3hot_delay() for very old Intel Atom SoCs,
but I have no idea about Skylake line of products.

Mika, Ilpo, do you have any ideas or comments on this?

-- 
With Best Regards,
Andy Shevchenko