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