Public bug reported:

Starting with kernel 5.17 the kernel supports the builtin privacy
screens built into the LCD panel of some new laptop models.

This means that the drm drivers will now return -EPROBE_DEFER from their
probe() method on models with a builtin privacy screen when the privacy
screen provider driver has not been loaded yet.

To avoid any regressions Ubuntu should modify its initrd generation tool
to include privacy screen provider drivers in the initrd (at least on
systems with a privacy screen), before 5.17 kernels start showing up in
the Ubuntu repos.

If this change is not made, then users using a graphical bootsplash
(plymouth) will get an extra boot-delay of up to 8 seconds
(DeviceTimeout in plymouthd.defaults) before plymouth will show and when
using disk-encryption where the LUKS password is requested from the
initrd, the system may fallback to text-mode after these 8 seconds.

I've written a patch with the necessary changes for dracut, which might
be useful as an example for how to deal with this, see:
https://github.com/dracutdevs/dracut/pull/1666

ATM the only kms driver using privacy screens is the i915 driver and the
only provider is the thinkpad_acpi driver. But both are likely to change
(and change soon!), so the detection really should be made dynamic as
has been done in the dracut patch.

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1954320

Title:
  Add privacy screen modules to the initrd

Status in linux package in Ubuntu:
  New

Bug description:
  Starting with kernel 5.17 the kernel supports the builtin privacy
  screens built into the LCD panel of some new laptop models.

  This means that the drm drivers will now return -EPROBE_DEFER from
  their probe() method on models with a builtin privacy screen when the
  privacy screen provider driver has not been loaded yet.

  To avoid any regressions Ubuntu should modify its initrd generation
  tool to include privacy screen provider drivers in the initrd (at
  least on systems with a privacy screen), before 5.17 kernels start
  showing up in the Ubuntu repos.

  If this change is not made, then users using a graphical bootsplash
  (plymouth) will get an extra boot-delay of up to 8 seconds
  (DeviceTimeout in plymouthd.defaults) before plymouth will show and
  when using disk-encryption where the LUKS password is requested from
  the initrd, the system may fallback to text-mode after these 8
  seconds.

  I've written a patch with the necessary changes for dracut, which
  might be useful as an example for how to deal with this, see:
  https://github.com/dracutdevs/dracut/pull/1666

  ATM the only kms driver using privacy screens is the i915 driver and
  the only provider is the thinkpad_acpi driver. But both are likely to
  change (and change soon!), so the detection really should be made
  dynamic as has been done in the dracut patch.

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https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1954320/+subscriptions


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