Add privacy screen modules to the initrd

[Hans de Goede]

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.

[Hans de Goede (j-w-r-degoede)]

The component here should be initramfs-tools which I selected at the "Report a bug" page, but I got at that page from the link at:
https://bugs.launchpad.net/ubuntu/+source/linux/ so I guess launchpad just decided to ignore my answer to "In what package did you find this bug?", because I came from the /ubuntu/+source/linux/ page ...

[Hans de Goede (j-w-r-degoede)]

Note I've also filed a bug against initramfs-tools in Debian for this, see: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1001409

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1954320

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Sebastien Bacher (seb128)]

I'm tagging the bug rls-jj-incoming for it to be reviewed as a target for the cycle, we don't plan to update to 5.17 afaik but the feature is requested by oem partners and we will likely end up cherry picking the kernel changes to the version we include

[Benjamin Drung (bdrung)]

We can just use similar code in initramfs-tools now that we use dracut-install from dracut.

[Launchpad Janitor (janitor)]

This bug was fixed in the package initramfs-tools - 0.142ubuntu16

---------------
initramfs-tools (0.142ubuntu16) noble; urgency=medium

  * Install nvmem, soc, power, and System Power Management Interface (SPMI)
    kernel modules on ARM/RISC-V for MediaTek boards (LP: #2038512)
  * Install intel_lpss_pci and spi_pxa2xx_platform kernel modules for keyboard
    on MacBook Pro 2017 (LP: #2042710)
  * Install surface_aggregator_registry for keyboard on Surface Laptop 4
    (LP: #2007050)
  * framebuffer: Add privacy screen modules to the initrd (LP: #1954320)

 -- Benjamin Drung <email address hidden> Tue, 14 Nov 2023 19:34:42 +0100