Bug#1125273: Black screen flash during GDM to GNOME session transition after 13.3 upgrade

[Antonio José Masiá]

The boot time from LUKS unlock to GDM has been roughly the same across all versions of Debian 13. This is something I've been noticing since I first installed Debian 13 — it didn't happen on Debian 12, where it was noticeably faster.

Antonio José Masiá
Software Engineer

ajmasia.dev at ysnp.link • betapermanente.link
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On Monday, January 26th, 2026 at 11:10, Antonio José Masiá <ajmasia.dev at ysnp.link> wrote:

> Hi Simon,
> 
> I installed the three packages from your repository:
> 
> gnome-shell_48.7-0+deb13u1+1+g122f544e6_amd64.deb
> gnome-shell-common_48.7-0+deb13u1+1+g122f544e6_all.deb
> gnome-shell-extension-prefs_48.7-0+deb13u1+1+g122f544e6_amd64.deb
> 
> After rebooting, the black screen flash during the GDM to GNOME session transition is gone. The issue appears to be fixed.
> 
> One additional observation: I'm noticing that it takes more than 10 seconds from unlocking the LUKS-encrypted root partition until GDM appears. Could this be related, or is this expected behavior?
> 
> Thank you for the quick response and the patched packages!
> 
> 
> 
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> 
> Antonio José Masiá
> Software Engineer
> 
> ajmasia.dev at ysnp.link • betapermanente.link
> 🔐 PGP fingerprint: 0F1AE0A0A325682DE8655B406F85F0F75CB8F8D3
> 
> 
> Aviso de privacidad. Esta cuenta es de uso personal. No compartas esta dirección sin mi consentimiento. Si recibiste este mensaje por error, infórmame lo antes posible. Si eres el destinatario previsto, trata este mensaje con discreción. Gracias.
> 
> Privacy Disclaimer. This is a personal email account. Do not share this address without my consent. If you received this message by mistake, please let me know. If you are the intended recipient, handle this message discreetly. Thank you.
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> 
> On Saturday, January 24th, 2026 at 11:54, Simon McVittie smcv at debian.org wrote:
> 
> > On Fri, 23 Jan 2026 at 10:29:33 +0000, Simon McVittie wrote:
> > 
> > > Not having a perfectly smooth animation is not a serious bug, and we
> > > have plenty of higher priorities. However, this might be related to
> > > other regressions that are more serious (#1125941, #1126174, #1125275)
> > > so it seems worthwhile to investigate.
> > 
> > Please try the version from
> > https://people.debian.org/~smcv/temp/2026/bug1125941/revert/
> > 
> > which addresses at least one of those regressions, and perhaps the one
> > you've reported as well.
> > 
> > smcv