kmscon: add terminal emulator for KMS devices - #161
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State machine for a VT220 terminal emulator, with no rendering or input handling of its own. kmscon builds on it. Signed-off-by: Daniel Golle <daniel@makrotopia.org>
A system without a framebuffer console has no text console at all. kmscon draws a terminal straight onto a DRM device, through OpenGL ES where the GPU allows and in software on the same device otherwise. Device access goes through libseat, so the seat owns the drm device and the vt rather than kmscon reaching for both itself. That needs seatd, which is a small daemon and already starts before this service. Built without the fbdev backend and with the built-in PC screen font, so it needs neither pango nor freetype. The service is off until enabled, so it does not take the display from whatever else is using it. Two patches are carried. The first keeps the unifont generator, a native helper linked against zlib for the build machine, out of a build that has the unifont backend disabled, which otherwise breaks cross compilation. The second stops an error loop: a render-only drm node answers NULL to drmModeGetResources, which the hotplug path treated as an error and returned from the poll handler, so kmscon wrote 776 error lines in eighty seconds on a board where the GPU enumerates before the display controller. Signed-off-by: Daniel Golle <daniel@makrotopia.org>
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A system without a framebuffer console has no text console at all.
kmscondraws a terminal straight onto a DRM device, through OpenGL ES where the GPU allows and in software on the same device otherwise.Device access goes through libseat, so the seat owns the drm device and the vt rather than kmscon reaching for both itself. That needs seatd, which is a small daemon and already starts before this service. Built without the fbdev backend and with the built-in PC screen font, so it needs neither pango nor freetype. The service is off until enabled, so it does not take the display from whatever else is using it.
Two patches are carried. The first keeps the unifont generator, a native helper linked against zlib for the build machine, out of a build that has the unifont backend disabled, which otherwise breaks cross compilation. The second stops an error loop: a render-only drm node answers NULL to drmModeGetResources, which the hotplug path treated as an error and returned from the poll handler, so kmscon wrote 776 error lines in eighty seconds on a board where the GPU enumerates before the display controller.