I've recently started using my own custom kernels in Ubuntu, and they are working without problems, with the exception that I don't have a text console when I press any of the key combinations Ctrl+Alt+Fn. I'm only seeing the Ubuntu splash screen. I thought it has something to do with the graphics settings in the kernel configuration under Device drivers -> Graphics support, particularly the Frame buffer settings. I have everything activated which is active in the kernel provided by Ubuntu, except for the fb drivers for specific chipsets other than nvidiafb, since I have an Nvidia card. Here are the enabled settings:
CONFIG_FB=y
CONFIG_FB_CMDLINE=y
CONFIG_FB_NOTIFY=y
CONFIG_FB_DDC=m
CONFIG_FB_BOOT_VESA_SUPPORT=y
CONFIG_FB_CFB_FILLRECT=y
CONFIG_FB_CFB_COPYAREA=y
CONFIG_FB_CFB_IMAGEBLIT=y
CONFIG_FB_SYS_FILLRECT=m
CONFIG_FB_SYS_COPYAREA=m
CONFIG_FB_SYS_IMAGEBLIT=m
CONFIG_FB_SYS_FOPS=m
CONFIG_FB_DEFERRED_IO=y
CONFIG_FB_BACKLIGHT=y
CONFIG_FB_MODE_HELPERS=y
CONFIG_FB_TILEBLITTING=y
CONFIG_FB_VESA=y
CONFIG_FB_EFI=y
CONFIG_FB_NVIDIA=m
CONFIG_FB_NVIDIA_I2C=y
CONFIG_FB_NVIDIA_BACKLIGHT=y
I wonder which kernel setting is responsible for the text console. My policy of configuring my own kernel was to disable everything I assumed I don't need, especially all the loadable kernel modules for specific devices that are included in the house kernel. Of course, I left many options unchanged as I didn't have a clue what they were about.
For my custom kernels, I have always been using the latest kernel source depended upon by the linux-source package, which currently is in version 4.15.0-45.48 from January 29. I'm using Ubuntu 18.04 LTS.
Update: I compiled a new kernel with the option CONFIG_FRAMEBUFFER_CONSOLE=y. With this kernel, I do have a text console, however, the proprietary Nvidia driver I've been using isn't loaded. What do I need to do to have that driver for my new kernel?
