From 320bfd91a985f2b945bad611c43add8a3a359845 Mon Sep 17 00:00:00 2001 From: Jonathan Neuschäfer Date: Fri, 14 Feb 2020 18:41:33 +0100 Subject: docs: admin-guide: Move edid.rst from driver-api MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Jonathan Corbet --- Documentation/admin-guide/edid.rst | 60 +++++++++++++++++++++++++++++++++++++ Documentation/admin-guide/index.rst | 1 + Documentation/driver-api/edid.rst | 60 ------------------------------------- Documentation/driver-api/index.rst | 1 - 4 files changed, 61 insertions(+), 61 deletions(-) create mode 100644 Documentation/admin-guide/edid.rst delete mode 100644 Documentation/driver-api/edid.rst diff --git a/Documentation/admin-guide/edid.rst b/Documentation/admin-guide/edid.rst new file mode 100644 index 000000000000..7dc07942ceb2 --- /dev/null +++ b/Documentation/admin-guide/edid.rst @@ -0,0 +1,60 @@ +.. 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/admin-guide/index.rst b/Documentation/admin-guide/index.rst index f1d0ccffbe72..5a6269fb8593 100644 --- a/Documentation/admin-guide/index.rst +++ b/Documentation/admin-guide/index.rst @@ -75,6 +75,7 @@ configure specific aspects of kernel behavior to your liking. cputopology dell_rbu device-mapper/index + edid efi-stub ext4 nfs/index 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 -- cgit v1.2.3