[arch-general] does using kms mean that you're stick to a framebuffer with specific resolution that you can't change?

the maximum resolution of my laptop is 1366x768, that's also the framebuffer size with kms enabled. the problem is when i attach a monitor with resolution 1920x1080 to it, the video output is at the top-left corner of the monitor. and i found myself unable to change the framebuffer size, appending video= option to the kernel command line doesn't take any effect. so, i wonder is there anyway to get a framebuffer with resolution 1920x1080 so i can benefit from the big monitor while still with kms enabled? kernel version : 3.10.0+ graphic card : intel hd4000