Proper Forma support (#4414)

* Enforce a known rotation on startup, to make sure we handle touch input coordinates properly.
* Proper FrontLight warmth support (thanks to @cairnsh & @pazos in #4291)!
* Fix the PageTurn buttons mapping to match Nickel's defaults
* Properly remap PageTurn buttons depending on the current rotation.
* Actually enable the Mk.7 screen refresh codepath on *all* Mk.7 devices (I'd messed up the device check...).
* Full accelerometer handling (includes a touch of refactoring regarding orientation handling in general).
* Fix insidiously broken USBMS behavior in Nickel after we exit on FW >4.8.

Fix #4291
Fix #3002

platform/kobo/koreader.sh

@@ -97,7 +97,7 @@ if [ "${FROM_NICKEL}" = "true" ]; then
     sync
     # stop kobo software because it's running
     # NOTE: We don't need to kill KFMon, it's smart enough not to allow running anything else while we're up
-    killall nickel hindenburg sickel fickel fmon 2>/dev/null
+    killall -TERM nickel hindenburg sickel fickel fmon 2>/dev/null
 fi
 
 # fallback for old fmon, KFMon and advboot users (-> if no args were passed to the script, start the FM)
@@ -135,6 +135,22 @@ if [ ! -n "${INTERFACE}" ]; then
 fi
 # end of value check of PLATFORM
 
+# If we're on a Forma, make sure we start in an orientation we know how to handle (i.e., Portrait, buttons on the Right)
+# Because NTX likes mounting panels in weird native rotations, this is actually FB_ROTATE_CCW (3).
+# And because shit gets even weirder, we have to echo 1 to get 3 (possibly because 2 is the native rotation, and 3 ^ 2 = 1).
+if [ "${PRODUCT}" = "frost" ]; then
+    # Only mess with this if we were started from Nickel
+    if [ "${FROM_NICKEL}" = "true" ]; then
+        # Don't do anything if we're already in the right orientation.
+        if [ "$(cat /sys/class/graphics/fb0/rotate)" -ne "3" ]; then
+            echo 1 >/sys/class/graphics/fb0/rotate
+            # Sleep a bit, for good measure
+            usleep 250000
+        fi
+    fi
+fi
+# NOTE: We don't have to restore anything on exit, nickel's startup process will take care of everything (pickel -> nickel).
+
 # Remount the SD card RW if it's inserted and currently RO
 if awk '$4~/(^|,)ro($|,)/' /proc/mounts | grep ' /mnt/sd '; then
     mount -o remount,rw /mnt/sd

platform/kobo/nickel.sh

@@ -6,6 +6,11 @@ PATH="/sbin:/bin:/usr/sbin:/usr/bin:/usr/lib:"
 # NOTE: LD_LIBRARY_PATH is the only late export from rcS we don't siphon in koreader.sh, for obvious reasons ;).
 export LD_LIBRARY_PATH="/usr/local/Kobo"
 
+# Reset PWD, and clear up our own custom stuff from the env while we're there, otherwise, USBMS may become very wonky on newer FW...
+# shellcheck disable=SC2164
+cd /
+unset OLDPWD EXT_FONT_DIR TESSDATA_PREFIX FROM_NICKEL STARDICT_DATA_DIR LC_ALL
+
 # Ensures fmon will restart. Note that we don't have to worry about reaping this, nickel kills on-animator.sh on start.
 (
     if [ "${PLATFORM}" = "freescale" ] || [ "${PLATFORM}" = "mx50-ntx" ] || [ "${PLATFORM}" = "mx6sl-ntx" ]; then
@@ -35,9 +40,10 @@ sync
 
 # And finally, simply restart nickel.
 # We don't care about horribly legacy stuff, because if people switch between nickel and KOReader in the first place, I assume they're using a decently recent enough FW version.
-# Last tested on an H2O running FW 4.7.x - 4.8.x
+# Last tested on an H2O & a Forma running FW 4.7.x - 4.12.x
 /usr/local/Kobo/hindenburg &
 LIBC_FATAL_STDERR_=1 /usr/local/Kobo/nickel -platform kobo -skipFontLoad &
+udevadm trigger &
 
 # Handle sdcard
 if [ -e "/dev/mmcblk1p1" ]; then