[Bug 1127552] New: Disable fbcon deferred takeover behavior?
http://bugzilla.opensuse.org/show_bug.cgi?id=1127552 Bug ID: 1127552 Summary: Disable fbcon deferred takeover behavior? Classification: openSUSE Product: openSUSE Tumbleweed Version: Current Hardware: Other OS: Other Status: NEW Severity: Normal Priority: P5 - None Component: Kernel Assignee: kernel-maintainers@forge.provo.novell.com Reporter: tiwai@suse.com QA Contact: qa-bugs@suse.de Found By: --- Blocker: --- Currently we enable CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER=y. This is essentially useful only for the i915 fastboot. But we don't enable i915 fastboot as default, and we even keep the plymouth boot splash. The deferred console takeover has an obvious drawback that it doesn't initialize the graphics screen. On a bare metal, it'll lead to the BIOS boot logo again, which is confusing. And more badly, on KVM, it just shows some garbage. So, for our default setup, it's better to turn off the deferred takeover. However, one problem is that, if we set CONFIG_FRAMEBUFER_CONSOLE_DEFERRED_TAKEOVER=n, the deferred takeover behavior can't be enabled dynamically since the option disables at the compile time. So, if user wants to re-enable the deferred takeover together with i915.fastboot=1, it won't work unless you recompile the kernel. The deferred takeover can be disabled via boot option "fbcon=nodefer", too. But it's not practical to set this. Maybe we'd need a patch to provide the default value in addition to the existing CONFIG_FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER... -- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.opensuse.org/show_bug.cgi?id=1127552 http://bugzilla.opensuse.org/show_bug.cgi?id=1127552#c1 --- Comment #1 from Takashi Iwai <tiwai@suse.com> --- BTW, the behavior on KVM isn't seen as default for non-EFI BIOS boot just because the kernel spews an error message ("efi: EFI_MEMMAP is not enabled") at the beginning, and fbcon appears immediately before starting the plymouth. But after turning this error off, KVM really shows only the garbage for the plymouth boot splash, then jumps to the X screen. After switch back to VT1 (via "chvt 1"), the fbcon still doesn't appear and the window remains blank until you hit some key. That's really odd. -- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.opensuse.org/show_bug.cgi?id=1127552 Takashi Iwai <tiwai@suse.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |patrik.jakobsson@suse.com, | |tzimmermann@suse.com -- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.opensuse.org/show_bug.cgi?id=1127552 http://bugzilla.opensuse.org/show_bug.cgi?id=1127552#c2 Felix Miata <mrmazda@earthlink.net> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |mrmazda@earthlink.net --- Comment #2 from Felix Miata <mrmazda@earthlink.net> --- (In reply to Takashi Iwai from comment #1)
But after turning this error off, KVM really shows only the garbage for the plymouth boot splash, then jumps to the X screen. After switch back to VT1 (via "chvt 1"), the fbcon still doesn't appear and the window remains blank until you hit some key. That's really odd.
It wouldn't be so odd if VT2-6 don't remain blank (no KVM or Plymouth here to check). There was a long discussion about VT1 being special on https://lists.debian.org/debian-user/2019/01/msg01073.html a month ago. -- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.opensuse.org/show_bug.cgi?id=1127552 http://bugzilla.opensuse.org/show_bug.cgi?id=1127552#c3 --- Comment #3 from Thomas Zimmermann <tzimmermann@suse.com> --- FTR a presentation about this was given at FOSDEM. [1] The display goes from BIOS logo to login screen. Windows does this and, according to the presentation, non-technical users expect it to some extend. It requires a number of changes to the 'boot services' (Grub, kernel console, Plymouth) to leave the display alone. I think we should disable it for now until the rest of our stack is ready. Having garbage on the screen is worse than what we have today. In the longer term, I wouldn't mind if we support this and maybe we can even make it run-time configurable. [1] https://fosdem.org/2019/schedule/event/flickerfree/ -- You are receiving this mail because: You are on the CC list for the bug.
http://bugzilla.opensuse.org/show_bug.cgi?id=1127552 http://bugzilla.opensuse.org/show_bug.cgi?id=1127552#c4 --- Comment #4 from Takashi Iwai <tiwai@suse.com> --- Yeah, that's my opinion, too. And, fundamentally, as long as we want keeping GRUB menu, the deferred fbcon takeover makes little sense. -- You are receiving this mail because: You are on the CC list for the bug.
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