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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 15:45:07 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 15:45:07 +0000
commit3b043b08c9b52424072db56be6636ff44c737e83 (patch)
treed64185acc33a046c8bb297641a16b01ec167eaa5 /docs/framebuffer
parentInitial commit. (diff)
downloadinitramfs-tools-3b043b08c9b52424072db56be6636ff44c737e83.tar.xz
initramfs-tools-3b043b08c9b52424072db56be6636ff44c737e83.zip
Adding upstream version 0.142.upstream/0.142upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'docs/framebuffer')
-rw-r--r--docs/framebuffer116
1 files changed, 116 insertions, 0 deletions
diff --git a/docs/framebuffer b/docs/framebuffer
new file mode 100644
index 0000000..453ac8f
--- /dev/null
+++ b/docs/framebuffer
@@ -0,0 +1,116 @@
+#!/bin/sh
+
+PREREQ=""
+prereqs()
+{
+ echo "$PREREQ"
+}
+case $1 in
+# get pre-requisites
+prereqs)
+ prereqs
+ exit 0
+ ;;
+esac
+
+
+# The options part of the kernel "video=" argument (i.e. everyting
+# after "video=<fbdriver>:") has very inconsistent rules.
+#
+# Generally the following applies:
+# 1) options are comma-separated
+# 2) options can be in either of these three forms:
+# <arg>=<value>, <arg>:<value>, <boolean-arg>.
+# 3) the "mode" or "mode_option" option (name depends on the framebuffer driver)
+# has the form <xres>x<yres>[M][R][-<bpp>][@<refresh>][i][m]
+# and may or may not start with "mode=" or "mode_option="
+# -> please adjust as necessary in the parse_video_opts() function
+#
+# When the options are used with modules, they need to be space-separated
+# and the following conversions are needed:
+# <arg>:<value> -> <arg>=<value>
+# <boolean-arg> -> <boolean-arg>=1
+# <modevalue> -> mode=<modevalue> or mode_option=<modevalue>
+parse_video_opts()
+{
+ local OPTS="$1"
+ local IFS=","
+
+ # Must be a line like video=<fbdriver>:<opt1>,[opt2]...
+ if [ "${OPTS}" = "${OPTS%%:*}" ]; then
+ return
+ fi
+ OPTS="${OPTS#*:}"
+ for opt in ${OPTS}; do
+ # Already in the "<arg>=<value>" form
+ if [ "${opt}" != "${opt#*=}" ]; then
+ printf "%s" "$opt "
+ # In the "<arg>:<value>" form
+ elif [ "${opt}" != "${opt#*:}" ]; then
+ printf "%s" "${opt%:*}=${opt#*:} "
+ # Presumably a modevalue without the "mode=" prefix
+ elif [ "${opt}" != "${opt#[0-9]*x[0-9]}" ]; then
+ # Adjust: mode= option?
+ printf "%s" "mode=$opt "
+ # ... or mode_option= option?
+ # printf "%s" "mode_option=$opt "
+ # Presumably a boolean
+ else
+ printf "%s" "${opt}=1 "
+ fi
+ done
+}
+
+FB=""
+OPTS=""
+
+# shellcheck disable=SC2013
+for x in $(cat /proc/cmdline); do
+ case ${x} in
+ vga=*)
+ FB="vesafb";
+ OPTS="";
+ ;;
+ video=*)
+ FB=${x#*=}
+ FB="${FB%%:*}"
+ OPTS="$(parse_video_opts "${x}")"
+ esac
+done
+
+# Module-specific workarounds
+case ${FB} in
+matroxfb)
+ # Map command line name to module name
+ FB=matroxfb_base
+ ;;
+intelfb|i810fb|i915)
+ # Needs AGP driver loaded
+ /sbin/modprobe intel-agp
+ ;;
+uvesafb)
+ # v86d requires /dev/zero and dev/mem, but udev haven't been started yet
+ [ -e /dev/zero ] || mknod -m 0666 /dev/zero c 1 5
+ [ -e /dev/mem ] || mknod -m 0640 /dev/mem c 1 1
+ ;;
+*)
+ ;;
+esac
+
+if [ -n "${FB}" ]; then
+ unset MODPROBE_OPTIONS
+ /sbin/modprobe -q fbcon
+ # shellcheck disable=SC2086
+ /sbin/modprobe -q ${FB} ${OPTS}
+fi
+
+if [ -e /proc/fb ]; then
+ # shellcheck disable=SC2034
+ while read -r fbno desc; do
+ if [ $((fbno < 32)) ]; then
+ mknod -m 0640 "/dev/fb${fbno}" c 29 "${fbno}"
+ fi
+ done < /proc/fb
+else
+ mknod -m 0640 /dev/fb0 c 29 0
+fi