I'm running Linux (Debian 10) on a Chromebook (Eve) using a stock Chrome OS kernel (4.4.x) with minor modifications. Everything runs (mostly) fine except that TTY console cannot be accessed via Ctrl+Alt+Fn, which does switch framebuffers as intended (i.e. Ctrl+F1 switches to DM and Crtl+F2 switches to desktop), but there doesn't seem to be any framebuffer for TTY emulation to display on (the screen just freezes upon Ctrl+F3 but desktop can be recovered just by Crtl+F2). Given that no log is displayed at boot, I'm guessing it's a kernel configuration issue. Relevant driver options related to TTY, console, and framebuffer are already enabled in the kernel configuration, and
tty devices are listed in
/dev. I tried compiling the Chrome OS kernel using stock Debian 10 configurations (for what overlap and default configuration for those that don't) and the TTY console did become available (but obviously a bunch of other things didn't work), so it isn't something that was written out of the Chrome OS kernel.
I compared the stock configurations between Eve and Debian and noted where different options are chosen on the same configuration items (there are 532 of these) and noted the following differences:
CONFIG_ITEM Debian Eve CONFIG_AGP_AMD64 y is not set CONFIG_AGP_SIS y is not set CONFIG_AGP_VIA y is not set CONFIG_VGA_SWITCHEROO y is not set CONFIG_DRM_FBDEV_EMULATION y is not set CONFIG_DRM_LOAD_EDID_FIRMWARE y is not set CONFIG_DRM_DP_CEC y is not set CONFIG_DRM_VGEM is not set y CONFIG_DRM_UDL is not set y CONFIG_DRM_CIRRUS_QEMU is not set m CONFIG_FIRMWARE_EDID y is not set CONFIG_FB_BOOT_VESA_SUPPORT y is not set CONFIG_FB_CFB_FILLRECT y is not set CONFIG_FB_CFB_COPYAREA y is not set CONFIG_FB_CFB_IMAGEBLIT y is not set CONFIG_FB_SYS_FILLRECT y is not set CONFIG_FB_SYS_COPYAREA y is not set CONFIG_FB_SYS_IMAGEBLIT y is not set CONFIG_FB_SYS_FOPS y is not set CONFIG_FB_TILEBLITTING y is not set CONFIG_FB_VESA y is not set CONFIG_FB_EFI y is not set CONFIG_FRAMEBUFFER_CONSOLE_ROTATION y is not set
But nothing changes after I compiled the kernel with these setting copied from Debian to the stock Eve configuration. Something else is amiss, and help is appreciated.