I can confirm this failure on a second machine and can add datapoints
relevant to the questions asked above.
Hardware: YAOSHI Series laptop, Intel iGPU (PCI 8086:7d67, "Found
meteorlake" in dmesg) in a hybrid configuration with an NVIDIA GPU.
Ubuntu 26.04 (linux-hwe-7.0).
Symptoms on this machine: internal eDP goes black after a DPMS blank or
after resume from suspend, with "PHY A failed to request refclk", "DDI
BUF A" timeout and "mismatch in dpll_hw_state" entries in the kernel
log. Long blank/suspend durations make the failure much more likely;
this occurred repeatedly on stock 7.0.0-31 before I applied the upstream
patch locally, and I verified that the stock 7.0.0-34 build still lacks
the fix.
Re: comment #3 (whether a mainline 7.3 build still reproduces): the
problem is fixed upstream by commit 28783a274e88 ("drm/i915/mtl+: Enable
PPS before PLL", Cc stable # v7.0+). It is in mainline since the 7.2
merge window and has been backported to 7.1.6 and 7.2.y, so any 7.3
mainline build already contains the fix and should not reproduce. This
is also why a fix cannot reach linux-hwe-7.0 through a regular stable
sync: the 7.0 series is EOL upstream (last release 7.0.14), so it would
need a manual cherry-pick.
Verification from this machine: I rebuilt i915.ko from the Ubuntu
7.0.0-31/7.0.0-34 sources with that upstream patch applied. Since
installing it, multiple long-duration DPMS blank/resume cycles (up to
~10.5 hours) and at least one deep S3 suspend/resume completed with zero
black screens and zero occurrences of the error lines above.
Request: please consider cherry-picking 28783a274e88 into linux-hwe-7.0
as an HW-enablement SRU. I am happy to test any proposed kernel builds
and provide journalctl logs on request.
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https://bugs.launchpad.net/bugs/2165830
Title:
(Arrow Lake C10 dpll_hw_state mismatch + "DDI BUF A" timeout on eDP
resume, kernel 7.0.0‑30
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