Hi,
We are working on an Asus Z550M shipping a baytrail processor. From
the 4.11 kernel we noticed that the system is not bootable anymore
since it hangs during boot when probing the r8169 driver, not even a
trace is available.
We bisected this problem down to commit 282a4e4 ("platform/x86: Enable
Atom PMC platform clocks").
We suspected that the problem is that one of the PMC clocks is being
used by the Ethernet board as XTAL clock and since it is not
explicitly claimed by the driver, it is gated at boot by the clock
framework, causing the system to hang.
We have a quirk downstream in place where we basically modified the
r8169 driver to claim the 25MHz pmc_plt_clk_4 clock, and this seems to
work fine, but we really want to find a more upstreamable and
definitive solution.
The best solution would probably be avoiding to gate the clocks at all
when booting if these are being already used by the firmware, but IIUC
this information is not always available in the enable clock register.
Any idea how to approach this issue? I guess in the future we will see
more platforms needing a quirk like this because of fancy clock
routings.
Thanks,
--
Carlo Caione
