Brainiarc7 · October 5, 2025 15:02 · May 27, 2019 · Jun 24, 2018 · Jun 24, 2018 · May 25, 2018
diff --git a/skylake-tuning-linux.md b/skylake-tuning-linux.md
@@ -34,17 +34,33 @@ It may be wise to install the `linux-firmware-nonfree` package as it may contain
 
 Now, to the real meat:
 
-**GUC loading on Skylake and above:**
-
-Add this to the kernel boot parameters on `/etc/default/grub`:
-
-    intel_pstate=skylake_hwp 
-
-
-The `intel_pstate=skylake_hwp option` enables Intel's Hardware P-States, known commonly by the marketing moniker "SpeedShift".
-Note that Intel's IOMMU for VT-d (enabled in the kernel by passing `intel_iommu=on` to the kernel boot options) cannot be used together with frame buffer compression (`i915.enable_fbc=1` argument passed to the i915). Frame Buffer Compression will be disabled automatically to prevent screen tearing in this case. 
-
-**Note:** The intel_pstate driver is the default since Linux 4.10 on SKL+. Thanks for the updates on this @pcordes and the correction on module options syntax in `/etc/modprobe.d/i915.conf`, @vinzent. Gr33ts ;-) 
+**See the supported module options:**
+
+Let's see if the features we're after are supported:
+
+```sh
+sudo modinfo i915 | egrep -i "guc|huc|dmc"
+
+firmware:       i915/bxt_dmc_ver1_07.bin
+firmware:       i915/skl_dmc_ver1_27.bin
+firmware:       i915/kbl_dmc_ver1_04.bin
+firmware:       i915/glk_dmc_ver1_04.bin
+firmware:       i915/cnl_dmc_ver1_07.bin
+firmware:       i915/icl_dmc_ver1_07.bin
+firmware:       i915/kbl_guc_ver9_39.bin
+firmware:       i915/bxt_guc_ver9_29.bin
+firmware:       i915/skl_guc_ver9_33.bin
+firmware:       i915/kbl_huc_ver02_00_1810.bin
+firmware:       i915/bxt_huc_ver01_8_2893.bin
+firmware:       i915/skl_huc_ver01_07_1398.bin
+parm:           enable_guc:Enable GuC load for GuC submission and/or HuC load. Required functionality can be selected using bitmask values. (-1=auto, 0=disable [default], 1=GuC submission, 2=HuC load) (int)
+parm:           guc_log_level:GuC firmware logging level. Requires GuC to be loaded. (-1=auto [default], 0=disable, 1..4=enable with verbosity min..max) (int)
+parm:           guc_firmware_path:GuC firmware path to use instead of the default one (charp)
+parm:           huc_firmware_path:HuC firmware path to use instead of the default one (charp)
+parm:           dmc_firmware_path:DMC firmware path to use instead of the default one (charp)
+```
+
+**Note:** The `intel_pstate driver` is the default since Linux 4.10 on SKL+. Thanks for the updates on this @pcordes and the correction on module options syntax in `/etc/modprobe.d/i915.conf`, @vinzent. Gr33ts ;-) 
 
 Then, update grub on Fedora:
 
@@ -87,7 +103,7 @@ In the following syntax:
 
     options i915 enable_guc=3
 
-Other safe options to pass are `enable_rc6=1`, `enable_fbc=1`, `enable_psr=1`, `disable_power_well=0` and `semaphores=1`
+Other safe options to pass are `enable_fbc=1`.
 
 
 **Reference:**
@@ -115,7 +131,7 @@ The following set of options should be generally safe to enable:
 
     /etc/modprobe.d/i915.conf
 
-    options i915 enable_dc=1 enable_fbc=1 semaphores=1 enable_guc=3
+    options i915 enable_fbc=1 enable_guc=3
 
 On Linux 4.16+, GuC firmware loading and submission is now handled by the `enable_guc` parameter in place of the former `enable_guc_loading=1` and `enable_guc_submission=1` parameters. Adjust as needed.
 
@@ -161,6 +177,89 @@ And also look at the output of:
 
     journalctl -b -o short-monotonic -k
 
+To confirm that the settings you wanted have been applied, run:
+
+```sh
+
+dmesg | grep -iE "huc|guc|dmc"
+```
+Output may look like this:
+
+```
+[    2.014699] Setting dangerous option enable_guc - tainting kernel
+[    2.019971] [drm] Finished loading DMC firmware i915/kbl_dmc_ver1_04.bin (v1.4)
+[    2.030651] [drm] HuC: Loaded firmware i915/kbl_huc_ver02_00_1810.bin (version 2.0)
+[    2.040648] [drm] GuC: Loaded firmware i915/kbl_guc_ver9_39.bin (version 9.39)
+[    2.051850] i915 0000:00:02.0: GuC firmware version 9.39
+[    2.051850] i915 0000:00:02.0: GuC submission enabled
+[    2.051851] i915 0000:00:02.0: HuC enabled
+
+```
+
+Which means you're good to go.
+
+You can also take a look at:
+
+1. GuC load status:
+
+```sh
+sudo cat /sys/kernel/debug/dri/0/i915_guc_load_status
+```
+
+```sh
+GuC firmware: i915/kbl_guc_ver9_39.bin
+	status: fetch SUCCESS, load SUCCESS
+	version: wanted 9.39, found 9.39
+	header: offset 0, size 128
+	uCode: offset 128, size 147392
+	RSA: offset 147520, size 256
+
+GuC status 0x800330ec:
+	Bootrom status = 0x76
+	uKernel status = 0x30
+	MIA Core status = 0x3
+
+Scratch registers:
+	 0: 	0xf0000000
+	 1: 	0x1
+	 2: 	0xc
+	 3: 	0x0
+	 4: 	0x2
+	 5: 	0x0
+	 6: 	0x7f2000
+	 7: 	0x8
+	 8: 	0x3
+	 9: 	0x403240
+	10: 	0x0
+	11: 	0x0
+	12: 	0x0
+	13: 	0x0
+	14: 	0x0
+	15: 	0x0
+```
+
+ 2. HuC load status:
+
+```sh
+sudo cat /sys/kernel/debug/dri/0/i915_huc_load_status
+```
+
+```sh
+ HuC firmware: i915/kbl_huc_ver02_00_1810.bin
+	status: fetch SUCCESS, load SUCCESS
+	version: wanted 2.0, found 2.0
+	header: offset 0, size 128
+	uCode: offset 128, size 218304
+	RSA: offset 218432, size 256
+
+HuC status 0x00006080:
+
+ ```
+
+ Also see: https://01.org/linuxgraphics/downloads/firmware
+
+
+
 
 **Screen corruption observed when waking up from suspend**
 

diff --git a/skylake-tuning-linux.md b/skylake-tuning-linux.md
@@ -115,15 +115,15 @@ The following set of options should be generally safe to enable:
 
     /etc/modprobe.d/i915.conf
 
-    options i915 enable_rc6=1 enable_fbc=1 semaphores=1 enable_guc=3
+    options i915 enable_dc=1 enable_fbc=1 semaphores=1 enable_guc=3
 
 On Linux 4.16+, GuC firmware loading and submission is now handled by the `enable_guc` parameter in place of the former `enable_guc_loading=1` and `enable_guc_submission=1` parameters. Adjust as needed.
 
 **RC6 sleep modes (`enable_rc6`):**
 
 You can experiment with higher values for enable_rc6, but your GPU may not support them or the activation of the other options:
 
-The available enable_rc6 values are a bitmask with bit values `RC6=1`, `RC6p=2`, `RC6pp=4[4]` - where "`RC6p`" and "`RC6pp`" are lower power states.
+The available `enable_dc` values are a bitmask with bit values `RC6=1`, `RC6p=2`, `RC6pp=4[4]` - where "`RC6p`" and "`RC6pp`" are lower power states.
 
 To confirm the current running RC6 level, you can look in sysfs:
 

diff --git a/skylake-tuning-linux.md b/skylake-tuning-linux.md
@@ -85,7 +85,7 @@ You can also add this to: `/etc/modprobe.d/i915.conf`
 
 In the following syntax:
 
-    options i915 enable_guc_loading=1 enable_guc_submission=1
+    options i915 enable_guc=3
 
 Other safe options to pass are `enable_rc6=1`, `enable_fbc=1`, `enable_psr=1`, `disable_power_well=0` and `semaphores=1`
 
@@ -115,7 +115,7 @@ The following set of options should be generally safe to enable:
 
     /etc/modprobe.d/i915.conf
 
-    options i915 enable_rc6=1 enable_fbc=1 semaphores=1 enable_guc_loading=1 enable_guc_submission=1
+    options i915 enable_rc6=1 enable_fbc=1 semaphores=1 enable_guc=3
 
 On Linux 4.16+, GuC firmware loading and submission is now handled by the `enable_guc` parameter in place of the former `enable_guc_loading=1` and `enable_guc_submission=1` parameters. Adjust as needed.
 

diff --git a/skylake-tuning-linux.md b/skylake-tuning-linux.md
@@ -116,6 +116,8 @@ The following set of options should be generally safe to enable:
     /etc/modprobe.d/i915.conf
 
     options i915 enable_rc6=1 enable_fbc=1 semaphores=1 enable_guc_loading=1 enable_guc_submission=1
+
+On Linux 4.16+, GuC firmware loading and submission is now handled by the `enable_guc` parameter in place of the former `enable_guc_loading=1` and `enable_guc_submission=1` parameters. Adjust as needed.
 
 **RC6 sleep modes (`enable_rc6`):**
 

diff --git a/skylake-tuning-linux.md b/skylake-tuning-linux.md
@@ -42,7 +42,9 @@ Add this to the kernel boot parameters on `/etc/default/grub`:
 
 
 The `intel_pstate=skylake_hwp option` enables Intel's Hardware P-States, known commonly by the marketing moniker "SpeedShift".
-Note that Intel's IOMMU for VT-d (enabled in the kernel by passing `intel_iommu=on` to the kernel boot options) cannot be used together with frame buffer compression (`i915.enable_fbc=1` argument passed to the i915). Frame Buffer Compression will be disabled automatically to prevent screen tearing in this case.
+Note that Intel's IOMMU for VT-d (enabled in the kernel by passing `intel_iommu=on` to the kernel boot options) cannot be used together with frame buffer compression (`i915.enable_fbc=1` argument passed to the i915). Frame Buffer Compression will be disabled automatically to prevent screen tearing in this case. 
+
+**Note:** The intel_pstate driver is the default since Linux 4.10 on SKL+. Thanks for the updates on this @pcordes and the correction on module options syntax in `/etc/modprobe.d/i915.conf`, @vinzent. Gr33ts ;-) 
 
 Then, update grub on Fedora:
 
@@ -58,23 +60,32 @@ And if you're still booting up in [legacy BIOS mode on an MBR-style partitioning
 
 
     grub2-mkconfig -o /boot/grub2/grub.cfg
+
+
+Then rebuild initramfs:
+
+**On Fedora**:
+
+    dracut --force
 
 
-**On Ubuntu:**
+**On Debian-based distributions:**
 
 Simply run:
 
+    sudo update-initramfs
+
     update-grub
 
 Then reboot.
 
-Your Skylake processor graphics will work just fine.
+Your modern Intel HD Graphics processor graphics will work just fine.
 
 You can also add this to: `/etc/modprobe.d/i915.conf`
 
 In the following syntax:
 
-    options i915.enable_guc_loading=1 i915.enable_guc_submission=1
+    options i915 enable_guc_loading=1 enable_guc_submission=1
 
 Other safe options to pass are `enable_rc6=1`, `enable_fbc=1`, `enable_psr=1`, `disable_power_well=0` and `semaphores=1`
 
@@ -104,7 +115,7 @@ The following set of options should be generally safe to enable:
 
     /etc/modprobe.d/i915.conf
 
-    options i915.enable_rc6=1 i915.enable_fbc=1 i915.semaphores=1
+    options i915 enable_rc6=1 enable_fbc=1 semaphores=1 enable_guc_loading=1 enable_guc_submission=1
 
 **RC6 sleep modes (`enable_rc6`):**
 
@@ -134,8 +145,12 @@ With the SNA acceleration method enabled, tearing may be observed. To fix this,
     Option "TearFree" "true"
 
 
+ This is not needed on server-grade SKUs where Xorg is unwelcome. 
+
+
 **Debugging:**
 
+
 Simply inspect dmesg:
 
     dmesg | grep drm

diff --git a/skylake-tuning-linux.md b/skylake-tuning-linux.md
@@ -38,10 +38,11 @@ Now, to the real meat:
 
 Add this to the kernel boot parameters on `/etc/default/grub`:
 
-    i915.enable_guc_loading=1 i915.enable_guc_submission=1 intel_pstate=skylake_hwp i915.enable_psr=1 i915.disable_power_well=0
+    intel_pstate=skylake_hwp 
 
 
 The `intel_pstate=skylake_hwp option` enables Intel's Hardware P-States, known commonly by the marketing moniker "SpeedShift".
+Note that Intel's IOMMU for VT-d (enabled in the kernel by passing `intel_iommu=on` to the kernel boot options) cannot be used together with frame buffer compression (`i915.enable_fbc=1` argument passed to the i915). Frame Buffer Compression will be disabled automatically to prevent screen tearing in this case.
 
 Then, update grub on Fedora:
 

diff --git a/skylake-tuning-linux.md b/skylake-tuning-linux.md
@@ -15,11 +15,11 @@ Note that the firmware for these GPUs is often packaged by your distributor, and
 
 Sample output:
 
-     /usr/lib/firmware/i915 
+    /usr/lib/firmware/i915 
     /usr/lib/firmware/i915/bxt_dmc_ver1_07.bin 
     /usr/lib/firmware/i915/kbl_dmc_ver1.bin
-     /usr/lib/firmware/i915/kbl_dmc_ver1_01.bin 
-     /usr/lib/firmware/i915/skl_dmc_ver1_23.bin 
+    /usr/lib/firmware/i915/kbl_dmc_ver1_01.bin 
+    /usr/lib/firmware/i915/skl_dmc_ver1_23.bin 
     /usr/lib/firmware/i915/skl_guc_ver1.bin 
     /usr/lib/firmware/i915/skl_guc_ver4.bin 
     /usr/lib/firmware/i915/skl_guc_ver6.bin 
@@ -38,10 +38,10 @@ Now, to the real meat:
 
 Add this to the kernel boot parameters on `/etc/default/grub`:
 
-    i915.enable_guc_loading=1 i915.enable_guc_submission=1 intel_pstate=skylake_hwp
+    i915.enable_guc_loading=1 i915.enable_guc_submission=1 intel_pstate=skylake_hwp i915.enable_psr=1 i915.disable_power_well=0
 
 
-The last option enables Intel's Hardware P-States, known commonly by the marketing moniker "SpeedShift".
+The `intel_pstate=skylake_hwp option` enables Intel's Hardware P-States, known commonly by the marketing moniker "SpeedShift".
 
 Then, update grub on Fedora:
 
@@ -75,7 +75,7 @@ In the following syntax:
 
     options i915.enable_guc_loading=1 i915.enable_guc_submission=1
 
-Other safe options to pass are `enable_rc6=1`, `enable_fbc=1` and `semaphores=1`
+Other safe options to pass are `enable_rc6=1`, `enable_fbc=1`, `enable_psr=1`, `disable_power_well=0` and `semaphores=1`
 
 
 **Reference:**

diff --git a/skylake-tuning-linux.md b/skylake-tuning-linux.md
@@ -128,7 +128,7 @@ Framebuffer compression may be unreliable or unavailable on Intel GPU generation
 
 **Tear-free video:**
 
-With the SNA acceleration method enabled, tearing may be observed. To fix this, enable the "`TearFree`" option in the driver by adding the following line to your configuration file:
+With the SNA acceleration method enabled, tearing may be observed. To fix this, enable the "`TearFree`" option in the driver by adding the following line to your xorg.conf (or ideally, a sub-configuration file under xorg.conf.d) configuration file:
 
     Option "TearFree" "true"
 

diff --git a/skylake-tuning-linux.md b/skylake-tuning-linux.md
@@ -38,7 +38,10 @@ Now, to the real meat:
 
 Add this to the kernel boot parameters on `/etc/default/grub`:
 
-    i915.enable_guc_loading=1 i915.enable_guc_submission=1
+    i915.enable_guc_loading=1 i915.enable_guc_submission=1 intel_pstate=skylake_hwp
+
+
+The last option enables Intel's Hardware P-States, known commonly by the marketing moniker "SpeedShift".
 
 Then, update grub on Fedora:
 

diff --git a/skylake-tuning-linux.md b/skylake-tuning-linux.md
@@ -139,7 +139,18 @@ Simply inspect dmesg:
 And also look at the output of:
 
     journalctl -b -o short-monotonic -k
+
+
+**Screen corruption observed when waking up from suspend**
+
+This is often observed as font and screen corruption in GTK+ applications (missing glyphs after suspend/resume).
+
+Should you experience missing font glyphs in GTK+ applications, the following workaround might help. Edit `/etc/environment` to add the following line:
 
+    /etc/environment
+    COGL_ATLAS_DEFAULT_BLIT_MODE=framebuffer
+
+See [this bug](https://bugs.freedesktop.org/show_bug.cgi?id=88584) here for more details.
 
 
 Thanks and regards,
@@ -149,3 +160,5 @@ Brainiarc7
 
 
 
+
+
diff --git a/skylake-tuning-linux.md b/skylake-tuning-linux.md
@@ -100,7 +100,7 @@ The following set of options should be generally safe to enable:
 
     /etc/modprobe.d/i915.conf
 
-    options i915 enable_rc6=1 enable_fbc=1 semaphores=1
+    options i915.enable_rc6=1 i915.enable_fbc=1 i915.semaphores=1
 
 **RC6 sleep modes (`enable_rc6`):**
 

diff --git a/skylake-tuning-linux.md b/skylake-tuning-linux.md
@@ -128,6 +128,17 @@ Framebuffer compression may be unreliable or unavailable on Intel GPU generation
 With the SNA acceleration method enabled, tearing may be observed. To fix this, enable the "`TearFree`" option in the driver by adding the following line to your configuration file:
 
     Option "TearFree" "true"
+
+
+**Debugging:**
+
+Simply inspect dmesg:
+
+    dmesg | grep drm
+
+And also look at the output of:
+
+    journalctl -b -o short-monotonic -k
 
 
 

diff --git a/skylake-tuning-linux.md b/skylake-tuning-linux.md
@@ -0,0 +1,140 @@
+**Tuning Intel Skylake and beyond for optimal performance and feature level support on Linux:**
+
+Note that on Skylake, Kabylake (and the now cancelled "Broxton") SKUs, functionality such as power saving, GPU scheduling and HDMI audio have been moved onto [binary-only firmware](https://01.org/linuxgraphics/downloads/firmware), and as such, the GuC and the HuC blobs must be loaded at run-time to access this functionality. 
+
+Enabling GuC and HuC on Skylake and above requires a few extra parameters be passed to the kernel before boot. 
+
+**Instructions provided for both Fedora and Ubuntu (including Debian):**
+
+
+Note that the firmware for these GPUs is often packaged by your distributor, and as such, you can confirm the firmware blob's availability by running:
+
+**1. On Fedora:**
+
+    rpm -ql linux-firmware | fgrep i915
+
+Sample output:
+
+     /usr/lib/firmware/i915 
+    /usr/lib/firmware/i915/bxt_dmc_ver1_07.bin 
+    /usr/lib/firmware/i915/kbl_dmc_ver1.bin
+     /usr/lib/firmware/i915/kbl_dmc_ver1_01.bin 
+     /usr/lib/firmware/i915/skl_dmc_ver1_23.bin 
+    /usr/lib/firmware/i915/skl_guc_ver1.bin 
+    /usr/lib/firmware/i915/skl_guc_ver4.bin 
+    /usr/lib/firmware/i915/skl_guc_ver6.bin 
+    /usr/lib/firmware/i915/skl_guc_ver6_1.bin 
+    /usr/share/doc/linux-firmware/LICENSE.i915
+
+**2. On Ubuntu:**
+
+    dpkg -L linux-firmware | fgrep i915
+
+It may be wise to install the `linux-firmware-nonfree` package as it may contain extra firmware blobs on Ubuntu releases *prior to 16.04LTS*. Don't install this on 16.04LTS and above.
+
+Now, to the real meat:
+
+**GUC loading on Skylake and above:**
+
+Add this to the kernel boot parameters on `/etc/default/grub`:
+
+    i915.enable_guc_loading=1 i915.enable_guc_submission=1
+
+Then, update grub on Fedora:
+
+(Run commands as root):
+
+For [EFI boot](https://wiki.archlinux.org/index.php/Unified_Extensible_Firmware_Interface) (More common):
+
+
+    grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg
+
+
+And if you're still booting up in [legacy BIOS mode on an MBR-style partitioning scheme](https://wiki.archlinux.org/index.php/partitioning#Master_Boot_Record) or with [CSM enabled](http://www.rodsbooks.com/efi-bootloaders/csm-good-bad-ugly.html) on Fedora for whatever reason:
+
+
+    grub2-mkconfig -o /boot/grub2/grub.cfg
+
+
+**On Ubuntu:**
+
+Simply run:
+
+    update-grub
+
+Then reboot.
+
+Your Skylake processor graphics will work just fine.
+
+You can also add this to: `/etc/modprobe.d/i915.conf`
+
+In the following syntax:
+
+    options i915.enable_guc_loading=1 i915.enable_guc_submission=1
+
+Other safe options to pass are `enable_rc6=1`, `enable_fbc=1` and `semaphores=1`
+
+
+**Reference:**
+
+See modinfo output for i915 for available GuC options:
+
+
+    modinfo i915 | grep guc
+
+
+**Further notes:**
+
+A list of all options along with short descriptions and default values can be generated with the following command:
+
+    $ modinfo -p i915
+
+To check which options are currently enabled, run:
+
+    # systool -m i915 -av
+
+You will note that many options default to -1, resulting in per-chip power-saving defaults. It is however possible to configure more aggressive powersaving by using module options.
+Warning: Diverting from the defaults will mark the kernel as tainted from Linux 3.18 onwards. This basically implies using other options than the per-chip defaults is considered experimental and not supported by the developers.
+
+The following set of options should be generally safe to enable:
+
+    /etc/modprobe.d/i915.conf
+
+    options i915 enable_rc6=1 enable_fbc=1 semaphores=1
+
+**RC6 sleep modes (`enable_rc6`):**
+
+You can experiment with higher values for enable_rc6, but your GPU may not support them or the activation of the other options:
+
+The available enable_rc6 values are a bitmask with bit values `RC6=1`, `RC6p=2`, `RC6pp=4[4]` - where "`RC6p`" and "`RC6pp`" are lower power states.
+
+To confirm the current running RC6 level, you can look in sysfs:
+
+    # cat /sys/class/drm/card0/power/rc6_enable
+
+If the value read is a lower number than expected, the other RC6 level are probably not supported. Passing `drm.debug=0xe` to the kernel boot options will add DRM debugging information to the kernel log - possibly including a line like this:
+
+    [drm:sanitize_rc6_option] Adjusting RC6 mask to 1 (requested 7, valid 1)
+
+**Framebuffer compression (`enable_fbc`):**
+
+Framebuffer compression may be unreliable or unavailable on Intel GPU generations before Sandy Bridge (generation 6). This results in messages logged to the system journal similar to this one:
+
+    kernel: drm: not enough stolen space for compressed buffer, disabling.
+
+
+**Tear-free video:**
+
+With the SNA acceleration method enabled, tearing may be observed. To fix this, enable the "`TearFree`" option in the driver by adding the following line to your configuration file:
+
+    Option "TearFree" "true"
+
+
+
+Thanks and regards,
+
+Brainiarc7
+
+
+
+