Okay, I built another older version of the kernel for testing. https://people.canonical.com/~acelan/bugs/lp1875254/ BTW, 5.4.0-28 is just released today, maybe you could install that new kernel and then try the test kernel to make sure you have a working kernel installed.
The test kernel on my XPS 13(2020) fixed the same issue as you described and doesn't introduce any regression. The patch applied on top of 5.4.0-21/5.4.0-26 is below commit which also could be found in the directory with the test kernel. >From 6a3916dc7d3dab9a7f41e3619532f928dc19a954 Mon Sep 17 00:00:00 2001 From: Kai Vehmanen <[email protected]> Date: Tue, 31 Dec 2019 16:00:07 +0200 Subject: [PATCH] drm/i915: Limit audio CDCLK>=2*BCLK constraint back to GLK only Revert changes done in commit f6ec9483091f ("drm/i915: extend audio CDCLK>=2*BCLK constraint to more platforms"). Audio drivers communicate with i915 over HDA bus multiple times during system boot-up and each of these transactions result in matching get_power/put_power calls to i915, and depending on the platform, a modeset change causing visible flicker. GLK is the only platform with minimum CDCLK significantly lower than BCLK, and thus for GLK setting a higher CDCLK is mandatory. For other platforms, minimum CDCLK is close but below 2*BCLK (e.g. on ICL, CDCLK=176.4kHz with BCLK=96kHz). Spec-wise the constraint should be set, but in practise no communication errors have been reported and the downside if set is the flicker observed at boot-time. Revert to old behaviour until better mechanism to manage probe-time clocks is available. The full CDCLK>=2*BCLK constraint is still enforced at pipe enable time in intel_crtc_compute_min_cdclk(). Bugzilla: https://gitlab.freedesktop.org/drm/intel/issues/913 Fixes: f6ec9483091f ("drm/i915: extend audio CDCLK>=2*BCLK constraint to more platforms") Signed-off-by: Kai Vehmanen <[email protected]> Reviewed-by: Matt Roper <[email protected]> Signed-off-by: Matt Roper <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected] (bacported from commit 1ee48a61aa57dbdbc3cd2808d8b28df40d938e44) Signed-off-by: AceLan Kao <[email protected]> ** Bug watch added: gitlab.freedesktop.org/drm/intel/issues #913 https://gitlab.freedesktop.org/drm/intel/issues/913 ** Tags added: oem-priority originate-from-1873148 somerville ** Changed in: linux (Ubuntu) Status: Confirmed => Invalid -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1875254 Title: Intermittent display blackouts on event To manage notifications about this bug go to: https://bugs.launchpad.net/hwe-next/+bug/1875254/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
