Re: [PATCH v3] mfd: intel-lpss: Set d3hot_delay to 0

[Andy Shevchenko]

On Mon, Oct 26, 2026 at 01:06:13AM +0530, Navon John Lukose wrote:
> Every runtime resume of an LPSS controller waits the default 10 ms
> d3hot_delay in pci_power_up() for the D3hot->D0 transition. Nothing
> misbehaves, but the wait adds latency. On Arrow Lake-H (Lenovo Yoga Pro 7
> 14IAH10) the touchpad's I2C controller autosuspends after 1 s idle, and
> the i2c-hid interrupt handler for the first report afterwards takes
> 12.6-14.4 ms.
> 
> The PCI spec asks for those 10 ms, but Mika Westerberg pointed out that
> the LPSS controllers are not really PCI-connected devices, so the delay
> is likely not needed. intel-lpss-pci already clears d3cold_delay,
> quirk_remove_d3hot_delay() drops d3hot_delay on several older Intel
> chipsets, Cherry Trail among them, and commit 815b4448198f ("i3c:
> mipi-i3c-hci-pci: Set d3hot_delay to 0 for Intel controllers") does the
> same for the Intel I3C controllers.
> 
> Set d3hot_delay to 0 as well. The handler above then takes 1.1-1.9 ms,
> with no I2C errors. Only Arrow Lake-H was tested.

Okay, we may go with this and I believe if any issue happens somewhere we
will know that sooner than later.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

-- 
With Best Regards,
Andy Shevchenko