Precised the aim of the kernel patch + some refactoring

CHANGELOG.md

@@ -9,3 +9,5 @@ Current
   <https://wiki.ubuntu.com/Kernel/BuildYourOwnKernel>. 
 - The linux patchs are now hosted on the repo.
 - Fixed and added precision on the KMS setup in the README.md
+- $DISPLAY environment var is not hardcoded anymore in gm-15khz but
+  simply appended to already set $DISPLAY screen number.

Makefile

@@ -21,7 +21,9 @@ LINUX_HEADERS_ALL_DEB = $(BUILDDIR)/linux-headers-$(KERNEL_BASE_VERSION)-$(KERNE
 LINUX_HEADERS_GENERIC_DEB = $(BUILDDIR)/linux-headers-$(KERNEL_BASE_VERSION)-$(KERNEL_ABI_NUMBER)-generic_$(KERNEL_BASE_VERSION)-$(KERNEL_ABI_NUMBER).$(KERNEL_UPLOAD_NUMBER)+patched15khz_amd64.deb
 LINUX_IMAGE_DEB = $(BUILDDIR)/linux-image-$(KERNEL_BASE_VERSION)-$(KERNEL_ABI_NUMBER)-generic_$(KERNEL_BASE_VERSION)-$(KERNEL_ABI_NUMBER).$(KERNEL_UPLOAD_NUMBER)+patched15khz_amd64.deb
 
-LINUX_15KHZ_PATCH = src/patch-3.19/linux-3.19.diff
+#LINUX_15KHZ_PATCH = src/patch-3.19/linux-3.19.diff
+LINUX_15KHZ_PATCH = src/linux-4.2.diff
+
 LINUX_AT9200_PATCH = src/patch-3.19/ati9200_pllfix-3.19.diff
 LINUX_AVGA3000_PATCH = src/patch-3.19/avga3000-3.19.diff
 
@@ -58,17 +60,16 @@ install:
 	mkdir -p $(PREFIX)/bin
 	cp src/bin/gm-15khz $(PREFIX)/bin/
 	@echo "Install finished"
-	@echo "Please reboot your computer using the new -patched15khz kernel"
+	@echo "Please reboot your computer to the new patched kernel"
 
 uninstall:
 	rm -r $(PREFIX)/lib/15khz-arcade-pkg
 	rm $(PREFIX)/bin/gm-15khz
 	apt-get install --reinstall xserver-xorg-video-nouveau
-	@echo "Uninstall finished."
-	@echo
-	@echo "The patched Linux kernel can't be safely uninstalled automatically while running."
-	@echo "Don't forget to uninstall it manually after booted to another kernel using:"
-	@echo "sudo apt-get remove linux-image-<version>-patched15khz linux-headers-<version>-patched15khz"
+	sudo apt-get remove $(notdir $(LINUX_HEADERS_ALL_DEB)) \
+		$(notdir $(LINUX_HEADERS_GENERIC_DEB)) \
+		$(notdir $(LINUX_IMAGE_DEB))
+	@echo "Uninstall finished. Please reboot your computer now"
 
 dist: 
 
@@ -124,6 +125,8 @@ $(GROOVYMAME_BIN): $(MAME_SRC_PKG) \
 	cd $(TMPDIR)/mame && patch -p0 --binary < $(realpath $(MAME_HI_PATCH))
 	cd $(TMPDIR)/mame && patch -p0 --binary < $(realpath $(MAME_GROOVY_PATCH))
 	cd $(TMPDIR)/mame && MAKEFLAGS= MFLAGS= make
+	cd $(TMPDIR)/mame && rm mame.zip
+	cd $(TMPDIR)/mame && make clean
 	mkdir -p $(BUILDDIR)/groovymame64
 	cp -r $(TMPDIR)/mame/* $(BUILDDIR)/groovymame64
 	rm -rf $(TMPDIR)/mame

README.md

@@ -6,39 +6,39 @@ Arcade videogames monitor running at 15Khz horizontal scan frequencies)
 to the VGA output of an Nvidia card using Ubuntu while keeping your
 primary screen connected.
 
-One of the aims is to play emulated retro arcade/console/computer games
+The goal is to play emulated retro arcade/console/computer games
 at real low resolutions on this monitor using emulators like MAME.
 
 Doing this is actually harder than it sounds because:
 
--   Linux kernel disallows 15Khz horizontal scan frequencies which are
-    used by theses old monitors — 31Khz is now the norm
+-   For some graphics card, and to enables some features, Linux kernel 
+    must be patched.
 -   Nvidia Drivers disallow resolutions lower than 320x200
 -   This setup requires not so obvious Xorg configuration
 -   Using 15khz monitors require the use of custom
     [modelines](https://en.wikipedia.org/wiki/XFree86_Modeline)
-    unhandled by Xorg nor Mame.
+    which must be setup manually — There are tools for that.
 
-This project helps to resolve theses issues by providing instructions
-and a `Makefile` which help generating:
+The content of this file helps to resolve theses issues by providing 
+instructions for generating:
 
 -   A patched Linux kernel wich allows 15Khz modelines as a deb package
 -   Patched nouveau drivers allowing low resolutions as a deb package
 -   Patched Mame binary using GroovyMame patch allowing Mame to generate
-    good 15khz compatible modelines on the fly
+    good 15khz compatible modelines on the fly.
 -   A Groovymame bash launcher which sets custom SDL env vars resolving
     some weird SDL related behaviors, sets the \$DISPLAY var on the
     right screen and tells the linker to use the patched nouveau.dri.so
     library.
 
-The generation of theses assets can be done automatically using `make`
-or manually by following the provided instructions.
+A Makefile is provided for automating the generation and configuration of
+most of the following steps.
 
 Motivation
 ----------
 
 The main purpose of this repository is to keep track and automate steps
-needed to achieve this goal. Second motivation is to share hoping that
+needed to achieve this goal. Second motivation is to share, hoping that
 it might help despite it fits my hardware/OS specifically. If you have
 suggestions or knowledges to make it more generic feel free to let me
 know.
@@ -85,7 +85,7 @@ the generation and installation of the assets.
 
     ``` {.sourceCode .bash}
     $ sudo apt-get build-dep linux-image mame
-    $ sudo apt-get install fakeroot
+    $ sudo apt-get install fakeroot qt5-default qtbase5-dev qtbase5-dev-tools
     ```
 
 2.  `git clone` this repository
@@ -151,11 +151,13 @@ So to launch a program on this screen, prefix the command-line with
 $ DISPLAY=:0.1 xrandr
 ```
 
+### Groovymame
+
 To launch groovymame64:
 
     $ gm-15khz sf2
 
-Note the absence of the prefix DISPLAY=:0.1 . It is useless because it
+Note the absence of the env var DISPLAY. It is useless because it
 is already set inside the `gm-15khz` bash launcher. `gm-15khz` is simply a
 wrapper of the `groovymame64` binary. All command line arguments
 following `gm-15khz` invocation are passed to the underlying
@@ -167,11 +169,23 @@ Detailled instructions for manual setup
 This chapter describes step by step how to connects your 15khz monitor
 on your computer having an Nvidia card using Ubuntu.
 
-### Allowing the Linux Kernel for 15khz modelines.
+### Patching the kernel
+
+As i am not the author of the patchs — thanks to arcadecontrol forum — it 
+is not very clear to me what is the aim of the patch but i presume 
+the following:
 
-Linux kernels disallows 15khz modelines to preserve monitors healths.
-Patchs for the kernel are made for bypassing this security. Here are the
-steps to follow to patch a kernel, compil and boot it.
+-   The patch allows 15khz modelines in `KMS` mode, which is the display 
+    engine used by the kernel at boot (splashscreen) before Xorg is 
+    launched
+-   The patch provide diff for ArcadeVGA and ATI cards. I think without
+    theses thoses cards are not allowed to handle low resolutions or 15khz
+    modelines.
+-   **The patch is not required for NVIDIA cards**, at least for mine. Only
+    patched nouveau drivers — as explained bellow — are required if the 
+    only goal is to play emulators and if you don't care about the 
+    booting phase.
+-   Patching the Kernel > 3.19, KMS feature doesn't seems to work.
 
 1.  Know the version of the installed Kernel:
 
@@ -360,7 +374,7 @@ setup, some environment variables must be set:
 SDL_JOYSTICK_ALLOW_BACKGROUND_EVENTS=1 \
     SDL_VIDEO_X11_XRANDR=0 \
     SDL_VIDEO_X11_XVIDMODE=0 \
-    DISPLAY=:0.1 \
+    DISPLAY=$DISPLAY.1 \
     ./groovymame sms sonic
 ```
 
@@ -379,8 +393,8 @@ The environment variables are explained below:
     action of theses SDL environnment variables is pretty hard
     understand but they fix it.
 
--   **DISPLAY=:0.1**: This tells Xorg to execute the program on the
-    Screen1 (CRT Screen). Note: This number can be :1.1 on your system.
+-   **DISPLAY=:$DISPLAY.1**: This tells Xorg to execute the program on the
+    Screen1 (CRT Screen).
 
 The `gm-15khz` bash launcher provided when installing the assets using
 the Makefile is basically a wrapper of GroovyMame which sets theses

src/bin/gm-15khz

@@ -12,9 +12,6 @@ export SDL_VIDEO_X11_XVIDMODE=0
 export SDL_JOYSTICK_ALLOW_BACKGROUND_EVENTS=1 
 
 # Tell X to use the second screen
-export DISPLAY=:0.1
-
-# Tell MESA to use the patched nouveau_dri.so
-export LIBGL_DRIVERS_PATH=$rootPath/../lib/15khz-arcade-pkg
+export DISPLAY=$DISPLAY.1
 
 $rootPath/../lib/15khz-arcade-pkg/groovymame64/mame64 $@