To reproduce: 1-use MGA gfxchip (KMS support unavailable) 2-include any of 791, 0x317, 794, 788, etc. appended to vga= on Grub Legacy cmdline 3-include 3 on cmdline 4-boot Actual results: 1-screen quickly blanks and stays that way 2-unusable vttys 3-vtty mode other than 80x25 impossible on unattended boot Expected results: 1-specified vga mode in effect 2-visible text on vttys Notes: 1-works as expected with 3.11.6-4 default and 3.11.13.g137a69e default. 2-result of specifying vga=ask and selecting any of the common framebuffer modes works as expected 3-specifying vga=normal works as expected 4-same brokenness with or without any valid video= on cmdline 5-same brokenness with or without nomodeset on cmdline 6-Plymouth not installed 7-tested only using openSUSE 13.2M0 and BS rpms
Can you attach a dmesg of the relevant good/bad boots. Want to know which video driver is actually being used here (and also if this is yet more simplefb breakage)
Created attachment 118911 [details] .tgz of dmesgs from 3.11.10 (OK) and 3.12.2.1 (no video) boots Dmesg from 3.12 made by typing on a black screen. In 3.11, Hot Plug Controller Driver @0.652203 is followed by vesafb: mode 1024x768x16 @0.652354 In 3.12, Hot Plug Controller Driver @0.654668 is followed by intel_idle does not run @0.654786 then GHES: HEST is not enabled @0.654834, with no vesa string anywhere
You probably enabled CONFIG_X86_SYSFB. Please see the Kconfig description for detailed information on it. We got a regression with driver transition with sysfbs. A patch is pending on LKML: http://thread.gmane.org/gmane.linux.kernel/1616367/focus=1616583 Can you give it a try?
And please, if you enable CONFIG_X86_SYSFB (which is 'n' by default), also enable CONFIG_FB_SIMPLE. The help text clearly states that if sysfb is enabled, you no longer get efi/vesa-framebuffer devices but instead the architecture generic simple-framebuffer. So if you really want vesafb, just set CONFIG_X86_SYSFB=n, otherwise, set it to y and enable simplefb.
I don't build, so can't test patches directly. The comment 0 MGA system also has Fedora 21 and 3.13.rc4 with CONFIG_X86_SYSFB unset and VGA= is working as expected. openSUSE 13.2's 3.12 & 3.13 have CONFIG_X86_SYSFB=y, where VGA= works OK with Intel (KMS) but not MGA (no KMS). It looks in https://bugzilla.novell.com/show_bug.cgi?id=855821 like CONFIG_X86_SYSFB will be disabled shortly if it hasn't been already in openSUSE kernels.
Most recently built openSUSE 13.2 3.12.5 and 3.13.rc7 kernels have CONFIG_X86_SYSFB unset, and VGA= is functioning normally using them.
s/3.13.rc7/3.13.0-rc3-7/