Re: [PATCH RESEND v2] PCI: imx6: Enable ASPM L1 only iff CLKREQ# is supported

[sashiko-bot@kernel.org]

> Since commit f3ac2ff14834 ("PCI/ASPM: Enable all ClockPM and ASPM
> states for devicetree platforms"), ASPM states are force enabled
> on all devicetree platforms. This causes PCI devices on some i.MX SoCs
> (for e.g. i.MX 8M Plus Kontron SMARC eval carrier) to enter L1 even
> though CLKREQ# is not supported (and consequently supports-clkreq is
> not set in pcie controller node of their DT), which causes the device to
> never wake up from L1.
> 
> Hence, disable L1 capability in the LNKCAP register if supports-clkreq
> is not set in the DT explicitly. For devices that set
> IMX_PCIE_FLAG_BROKEN_SUSPEND, disable L1 on resume as well, as these
> skip imx_pcie_host_init().
> 
> Note, the logic here is very similar to 613f3255a35a, only difference
> is that leaving L0s enabled does not cause issues (at least
> I never encountered them myself when testing on the device) as its
> not dependent on CLKREQ# being physically there.
> Since there is already a way of specifying its presence in the DT,
> the driver should be aware and disable L1.
> 
> Fixes: f3ac2ff14834 ("PCI/ASPM: Enable all ClockPM and ASPM states for devicetree platforms")
> Signed-off-by: Michal Gorlas <michal.gorlas@9elements.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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