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author | Jonathan Neuschäfer <j.neuschaefer@gmx.net> | 2020-02-14 20:41:33 +0300 |
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committer | Jonathan Corbet <corbet@lwn.net> | 2020-02-19 14:10:31 +0300 |
commit | 320bfd91a985f2b945bad611c43add8a3a359845 (patch) | |
tree | 8689309bfb44e79b6ada23c9041afd6cfb8abd39 /Documentation/driver-api | |
parent | 1733ec77d34059cd67a7b9677fe2fd3ef977afb3 (diff) | |
download | linux-320bfd91a985f2b945bad611c43add8a3a359845.tar.xz |
docs: admin-guide: Move edid.rst from driver-api
This document describes actions that an admin can do, rather than
interfaces available to driver developers, so admin-guide seems to
be a more appropriate place for it.
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r-- | Documentation/driver-api/edid.rst | 60 | ||||
-rw-r--r-- | Documentation/driver-api/index.rst | 1 |
2 files changed, 0 insertions, 61 deletions
diff --git a/Documentation/driver-api/edid.rst b/Documentation/driver-api/edid.rst deleted file mode 100644 index 7dc07942ceb2..000000000000 --- a/Documentation/driver-api/edid.rst +++ /dev/null @@ -1,60 +0,0 @@ -.. 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. The code -(see drivers/gpu/drm/drm_edid_load.c) contains built-in data sets for -commonly used screen resolutions (800x600, 1024x768, 1280x1024, 1600x1200, -1680x1050, 1920x1080) as binary blobs, but the kernel source tree does -not contain code to create these data. In order to elucidate the origin -of the built-in binary EDID blobs and to facilitate the creation of -individual data for a specific misbehaving monitor, commented sources -and a Makefile environment are given here. - -To create binary EDID and C source code files from the existing data -material, simply type "make". - -If you want to create your own EDID file, copy the file 1024x768.S, -replace the settings with your own data and add a new target to the -Makefile. Please note that the EDID data structure expects the timing -values in a different way as compared to the standard X11 format. - -X11: - HTimings: - hdisp hsyncstart hsyncend htotal - VTimings: - vdisp vsyncstart vsyncend vtotal - -EDID:: - - #define XPIX hdisp - #define XBLANK htotal-hdisp - #define XOFFSET hsyncstart-hdisp - #define XPULSE hsyncend-hsyncstart - - #define YPIX vdisp - #define YBLANK vtotal-vdisp - #define YOFFSET vsyncstart-vdisp - #define YPULSE vsyncend-vsyncstart diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst index 0ebe205efd0c..ea3003b3c5e5 100644 --- a/Documentation/driver-api/index.rst +++ b/Documentation/driver-api/index.rst @@ -74,7 +74,6 @@ available subsections can be seen below. connector console dcdbas - edid eisa ipmb isa |