Re: [PATCH v2] mfd: intel-lpss: Set d3hot_delay to 0

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Thu, Oct 22, 2026 at 09:34:53AM +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().
> 
> The PCI spec asks for those 10 ms on D3hot->D0. Mika pointed out that the
> LPSS controllers are not really PCI-connected devices, so the delay is
> likely not needed. quirk_remove_d3hot_delay() drops it 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.
> 
> Nothing misbehaves with the delay in place, so this only shortens resume.
> On Arrow Lake-H (Lenovo Yoga Pro 7 14IAH10) the touchpad's I2C controller
> autosuspends after 1 s idle, and the first report afterwards waits for the
> resume. With d3hot_delay set to 0 the i2c-hid interrupt handler for that
> report takes 1.1-1.9 ms instead of 12.6-14.4 ms, with no I2C errors. Only
> Arrow Lake-H was tested.
> 
> Signed-off-by: Navon John Lukose <navonjohnlukose@gmail.com>

Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>