1.. SPDX-License-Identifier: GPL-2.0 2 3==== 4EDID 5==== 6 7In the good old days when graphics parameters were configured explicitly 8in a file called xorg.conf, even broken hardware could be managed. 9 10Today, with the advent of Kernel Mode Setting, a graphics board is 11either correctly working because all components follow the standards - 12or the computer is unusable, because the screen remains dark after 13booting or it displays the wrong area. Cases when this happens are: 14 15- The graphics board does not recognize the monitor. 16- The graphics board is unable to detect any EDID data. 17- The graphics board incorrectly forwards EDID data to the driver. 18- The monitor sends no or bogus EDID data. 19- A KVM sends its own EDID data instead of querying the connected monitor. 20 21Adding the kernel parameter "nomodeset" helps in most cases, but causes 22restrictions later on. 23 24As a remedy for such situations, the kernel configuration item 25CONFIG_DRM_LOAD_EDID_FIRMWARE was introduced. It allows to provide an 26individually prepared or corrected EDID data set in the /lib/firmware 27directory from where it is loaded via the firmware interface. 28