I did a full kernel build and I'm afraid either it didn't work or I did something wrong...
Here're my steps:
mkdir src
cd src
wget https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.2.tar.xz
tar -xf ./linux-5.2.tar.xz
git clone https://github.com/D0023R/linux_kernel_15khz.git
cd linux-5.2/
nano Makefile
# added -15KHz-intel to the version string
sudo su
patch -p1 < ../linux_kernel_15khz/linux-5.2/03_linux_15khz.diff
patch -p1 < ../linux_kernel_15khz/linux-5.2/04_linux_15khz_interlaced_mode_fix.diff
patch -p1 < ../linux_kernel_15khz/linux-5.2/05_linux_15khz_scanoutpos.diff
patch -p1 < ../i915_15khz_test.patch
# had to apply the following patch because of equal names
patch -p1 < ../8-8-drivers-regulator-88pm800-fix-warning-same-module-names.diff
cp /usr/src/linux-headers-5.2.0-050200-generic/.config .
# ran into another error because of a missing dependancy:
apt-get install libelf-dev
make -j$(nproc)
make modules_install
make install
update-grub
Then I bootet into the 5.2xxxx-15KHz-intel kernel and tried some modelines, all with the same message:
xrandr: Configure crtc 0 failed
Here're the modelines I tested:
modeline '240x240' 4,83 240 252 276 310 240 243 246 265 -hsync -vsync
modeline '256x240' 5,30 256 272 296 336 240 244 247 261 -hsync -vsync
modeline '256x256' 5,36 256 268 292 330 256 257 260 273 -hsync -vsync
modeline '256x264' 5,35 256 268 292 330 264 265 268 278 -hsync -vsync
modeline '288x240' 5,84 288 296 328 368 240 243 246 265 -hsync -vsync
modeline '296x240' 5,95 296 304 336 376 240 243 246 264 -hsync -vsync
modeline '304x240' 6,20 304 320 352 396 240 243 246 264 -hsync -vsync
modeline '320x240' 6,45 320 336 368 414 240 242 245 264 -hsync -vsync
modeline '320x256' 6,68 320 340 372 416 256 257 260 268 -hsync -vsync
modeline '336x240' 6,83 336 352 384 433 240 243 246 264 -hsync -vsync
modeline '352x256' 7,28 352 368 400 450 256 257 260 271 -hsync -vsync
modeline '352x264' 7,35 352 365 405 452 264 265 268 284 -hsync -vsync
modeline '352x288' 7,40 352 368 408 464 288 289 292 312 -hsync -vsync
modeline '368x240' 7,47 368 384 424 478 240 243 246 264 -hsync -vsync
modeline '384x288' 7,85 384 400 440 496 288 289 292 309 -hsync -vsync
modeline '392x240' 8,00 392 408 448 504 240 243 246 265 -hsync -vsync
modeline '400x256' 8,08 400 416 456 519 256 268 271 297 -hsync -vsync
modeline '448x240' 9,16 448 464 512 576 240 243 246 265 -hsync -vsync
modeline '512x240' 10,68 512 544 600 672 240 243 246 265 -hsync -vsync
modeline '512x288' 10,68 512 544 600 672 288 289 292 312 -hsync -vsync
modeline '632x264' 13,00 632 664 728 824 264 265 268 278 -hsync -vsync
modeline '640x240' 13,22 640 672 736 832 240 243 246 265 -hsync -vsync
modeline '640x288' 13,10 640 672 736 832 288 289 292 309 -hsync -vsync
And here's the output of lsmod:
Module Size Used by
gpio_ich 16384 0
coretemp 20480 0
i915 1867776 8
kvm 630784 0
irqbypass 16384 1 kvm
snd_hda_codec_realtek 114688 1
hp_wmi 16384 0
sparse_keymap 16384 1 hp_wmi
snd_hda_codec_generic 77824 1 snd_hda_codec_realtek
ledtrig_audio 16384 2 snd_hda_codec_generic,snd_hda_codec_realtek
drm_kms_helper 184320 1 i915
snd_hda_intel 40960 2
wmi_bmof 16384 0
serio_raw 20480 0
input_leds 16384 0
drm 471040 7 drm_kms_helper,i915
joydev 24576 0
snd_hda_codec 126976 3 snd_hda_codec_generic,snd_hda_intel,snd_hda_codec_realtek
i2c_algo_bit 16384 1 i915
fb_sys_fops 16384 1 drm_kms_helper
snd_hda_core 90112 4 snd_hda_codec_generic,snd_hda_intel,snd_hda_codec,snd_hda_codec_realtek
syscopyarea 16384 1 drm_kms_helper
snd_hwdep 20480 1 snd_hda_codec
sysfillrect 16384 1 drm_kms_helper
snd_pcm 102400 3 snd_hda_intel,snd_hda_codec,snd_hda_core
sysimgblt 16384 1 drm_kms_helper
snd_timer 36864 1 snd_pcm
snd 81920 11 snd_hda_codec_generic,snd_hwdep,snd_hda_intel,snd_hda_codec,snd_hda_codec_realtek,snd_timer,snd_pcm
soundcore 16384 1 snd
lpc_ich 24576 0
mei_me 40960 0
mei 102400 1 mei_me
tpm_infineon 16384 0
mac_hid 16384 0
sch_fq_codel 20480 2
parport_pc 36864 0
ppdev 24576 0
lp 20480 0
parport 53248 3 parport_pc,lp,ppdev
ip_tables 32768 0
x_tables 40960 1 ip_tables
autofs4 45056 2
hid_generic 16384 0
usbhid 53248 0
hid 131072 2 usbhid,hid_generic
ahci 40960 1
psmouse 151552 0
libahci 32768 1 ahci
e1000e 249856 0
pata_acpi 16384 0
video 49152 1 i915
wmi 28672 2 hp_wmi,wmi_bmof