Update (November 18, 2017): After receiving lots of feedback about issues with setting up the graphics to an adequate level, I rewrote that part of the blog post. I've also added instructions on actually enabling the use of normal graphics drivers since many people unknowingly used Mesa's software rasterizer, which causes all sorts of issues.

Recently, I got a new laptop, a Dell XPS 15 9560 with 4k display, 32 GiBs of RAM and 1 TiB M.2 SSD drive. Quite nice specs, aren't they ?

Unfortunately, I wasn't able to purchase it without Windows pre-installed. But they didn't last long since I wiped the hard drive and installed Fedora 26 on it.

Let me briefly describe my experience and guide you through some trickier parts of the setup.

Configuring UEFI to work with Fedora 26

Before installing Fedora 26 on the system, it is necessary to modify some UEFI settings. They are nicely summed up in the ArchWiki page for this laptop:

• Change the SATA Mode from the default RAID to AHCI. This will allow Linux to detect the NVMe SSD.
• Change Fastboot to Thorough in POST Behaviour. This will prevent intermittent boot failures.

Booting Fedora 26 from a live USB

The naive approach to just boot the computer from a live USB with Fedora 26 Workstation image and wait for the live GNOME session to appear didn't work. Fedora hangs after the Started User Manager for UID 1000 systemd unit starts.

Fortunately, Ask Fedora has an answer to this problem, which is to select Troubleshooting from GRUB's boot menu and then choose Start in basic graphics mode. The live GNOME session should work fine after that.

Installing Fedora 26 to the hard drive

This works smoothly. Just select Install to Hard Drive option to start Anaconda, Fedora's installer, and follow its instructions.

After installation, make sure to update all packages to get the latest kernel (4.12 at the time of writing) and other important updates which will make Fedora run smoother on this laptop.

Setting up graphics

The laptop comes with a discrete GPU, the NVIDIA GeForce GTX 1050 Mobile (GP107M), and an integrated GPU, the Intel HD Graphics 630 (Kaby Lake GT2).

Enabling the use of normal graphics drivers

Since we needed to use the basic graphics mode when booting Fedora 26 from a live USB, the installer "baked" this information into the newly installed system. While this is a safe choice, i.e. the system is guaranteed to successfully boot into graphics mode, it also means that no advanced graphics features will work. When I used the system in this mode, GNOME didn't detect that it runs on a HiDPI screen and hence everything on the screen was too small. Connecting an external monitor also didn't work and moving around the UI elements was slow and sluggish.

The reason for this is that the installer added the nomodeset kernel command line option to GRUB's settings. Passing the nomodeset option to the kernel disables Kernel Mode setting (KMS) which in turn forces the system to fallback to using Mesa's Gallium llvmpipe driver which is a software rasterizer that runs on the CPU.

To enable normal graphics drivers, edit /etc/default/grub and remove nomodeset from the contents of the GRUB_CMDLINE_LINUX variable.

Afterwards, run sudo grub2-mkconfig -o /etc/grub2-efi.cfg to regenerate GRUB's configuration and reboot the system.

A rocky road when trying to use NVIDIA discrete GPU with Nouveau drivers

Unfortunately, NVIDIA GeForce GTX 1050 Mobile (GP107M) doesn't work well with the Nouveau drivers yet (as of kernel 4.12).

Practically, this means that the system will fail to boot (similarly as described above) if one doesn't disable Nouveau's power management by passing the nouveau.runpm=0 parameter to the kernel at boot. More information in Red Hat's Bugzilla #1447677.

Unfortunately, that's not enough. After successfully booting the system into a graphical session, I soon started encountering soft kernel lockups due to Nouveau driver. The logs showed the following:

NMI watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [plymouthd:423]

[ ... output trimmed ... ]

CPU: 1 PID: 423 Comm: plymouthd Not tainted 4.12.9-300.fc26.x86_64 #1
Hardware name: Dell Inc. XPS 15 9560/05FFDN, BIOS 1.3.4 06/08/2017
task: ffff92a115bea640 task.stack: ffffa79943d7c000

[ ... output trimmed ... ]

Call Trace:
 ? nv04_timer_read+0x48/0x60 [nouveau]
 nvkm_timer_read+0xf/0x20 [nouveau]
 nvkm_pmu_reset+0x71/0x170 [nouveau]
 nvkm_pmu_preinit+0x12/0x20 [nouveau]
 nvkm_subdev_preinit+0x34/0x110 [nouveau]
 nvkm_device_init+0x60/0x270 [nouveau]
 nvkm_udevice_init+0x48/0x60 [nouveau]
 nvkm_object_init+0x3f/0x190 [nouveau]
 nvkm_object_init+0xa3/0x190 [nouveau]
 nvkm_client_resume+0xe/0x10 [nouveau]
 nvif_client_resume+0x17/0x20 [nouveau]
 nouveau_do_resume+0x40/0xe0 [nouveau]
 nouveau_pmops_runtime_resume+0x91/0x150 [nouveau]

[ ... output trimmed ... ]

Looking through systemd journal soon revealed other kernel tracebacks related to the Nouveau driver:

nouveau 0000:01:00.0: bus: MMIO read of 00000000 FAULT at 409800 [ TIMEOUT ]
[drm:i915_gem_idle_work_handler [i915]] *ERROR* Timeout waiting for engines to idle
nouveau 0000:01:00.0: timeout
------------[ cut here ]------------
WARNING: CPU: 1 PID: 4100 at drivers/gpu/drm/nouveau/nvkm/engine/gr/gf100.c:1501 gf100_gr_init_ctxctl+0x81f/0x9a0 [nouveau]

[ ... output trimmed ... ]

Hardware name: Dell Inc. XPS 15 9560/05FFDN, BIOS 1.3.4 06/08/2017
task: ffff8d8261e00000 task.stack: ffffa5c91190c000

[ ... output trimmed ... ]

Call Trace:
 gp100_gr_init+0x6f0/0x720 [nouveau]
 gf100_gr_init_+0x55/0x60 [nouveau]
 nvkm_gr_init+0x17/0x20 [nouveau]
 nvkm_engine_init+0x68/0x1f0 [nouveau]
 nvkm_subdev_init+0xb0/0x200 [nouveau]
 nvkm_engine_ref+0x4f/0x70 [nouveau]
 nvkm_ioctl_new+0x2b4/0x300 [nouveau]
 ? nvkm_fifo_chan_dtor+0xe0/0xe0 [nouveau]
 ? gf100_gr_init_fw.isra.8+0x50/0x50 [nouveau]
 nvkm_ioctl+0x118/0x280 [nouveau]
 nvkm_client_ioctl+0x12/0x20 [nouveau]
 nvif_client_ioctl+0x26/0x30 [nouveau]
 usif_ioctl+0x637/0x750 [nouveau]
 nouveau_drm_ioctl+0xaf/0xc0 [nouveau]

[ ... output trimmed ... ]

---[ end trace 1ee905135b51d0af ]---
nouveau 0000:01:00.0: gr: init failed, -16
nouveau 0000:01:00.0: timeout
------------[ cut here ]------------
WARNING: CPU: 2 PID: 4100 at drivers/gpu/drm/nouveau/nvkm/subdev/mmu/gf100.c:190 gf100_vm_flush+0x1ab/0x1c0 [nouveau]

[ ... output trimmed ... ]

Hardware name: Dell Inc. XPS 15 9560/05FFDN, BIOS 1.3.4 06/08/2017
task: ffff8d8261e00000 task.stack: ffffa5c91190c000

[ ... output trimmed ... ]

Call Trace:
 nvkm_vm_unmap_at+0xbc/0x100 [nouveau]
 nvkm_vm_unmap+0x1b/0x20 [nouveau]
 nouveau_gem_object_close+0x1aa/0x1c0 [nouveau]
 drm_gem_object_release_handle+0x4b/0x90 [drm]
 drm_gem_handle_delete+0x58/0x80 [drm]
 drm_gem_close_ioctl+0x20/0x30 [drm]
 drm_ioctl+0x213/0x4d0 [drm]
 ? drm_gem_handle_create+0x40/0x40 [drm]
 ? sock_write_iter+0x8c/0xf0
 nouveau_drm_ioctl+0x72/0xc0 [nouveau]
---[ end trace 1ee905135b51d0b0 ]---

Flying high after starting to use Intel's integrated GPU

After encountering a Nouveau developer's (Rhys Kidd) answer to a bug report for a similar issue that I described above on freedesktop.org's Bugzilla on Aug 17, 2017:

Nouveau has difficulties with the GTX 1050 Mobile (GP107/NV137) around power state up/down. I'd suggest you continue to follow that bug report for further updates.

Whilst nouveau.runpm=0 assists a little bit, for now, to improve the experience on the XPS 9560 you should use nouveau.modeset=0 (although that does mean the Nvidia GPU is unavailable for use). This suggestion might change with future kernel releases.

I decided to follow his suggestion and disable the Nouveau driver by adding nouveau.modeset=0 to the kernel's command line options. In my observations so far, everything is working smootly:

• automatic scaling of GNOME's interface (it even works if you use laptop's built-in HiDPI display in combination with an external non-HiDPI display),
• fast day to day work (i.e. no sluggishness),
• suspend and resume (works even after many suspend and resume cycles or if you resume the laptop with/without an external display),
• battery life is great (I haven't done any proper benchmarks, but it easily lasts around 4 hours of my ordinary programming work).

To make this permament, edit /etc/default/grub and append nouveau.modeset=0 to the contents of the GRUB_CMDLINE_LINUX variable.

Afterwards, run sudo grub2-mkconfig -o /etc/grub2-efi.cfg to regenerate GRUB's configuration.

Updating firmware to version 1.3.4+

It is important to upgrade the laptop's firmware to (at least) version 1.3.4 since it fixes a serious issue with Intel's Skylake and Kaby Lake architectures where the CPU could dangerously misbehave when hyper-threading is enabled.

Fortunately, Dell has put Linux users in the prime seat and offers seamless firmware updates on Linux via Richard Hughes's excellent fwupd tool.

To update the firmware using command line, simply run:

fwupdmgr refresh
fwupdmgr get-updates

to see the list of available updates. To download the available update and install it after reboot, run:

fwupdmgr update

Alternatively, you can also update the firmware using GNOME's Software app.

Issues with wireless performance on kernel 4.12

I've experienced an order of magnitude wireless performance drop after upgrading from kernel-4.11.11-300.fc26.x86_64 to kernel-4.12.5-300.fc26 with the Qualcomm Atheros QCA6174 802.11ac wireless network adapter that is installed in the laptop. The reported wireless link speed is in 1 - 6 Mbps range, which is very low.

I haven't had time to investigate this further yet.

Conclusion

Overall, my experience (minus the problems with NVIDIA's graphics card and its open-source drivers and the wireless performance issue) has been quite positive.

Sadly, getting all the features of a new laptop to work seamlessly after it launches is not there yet and one still has to be quite knowledgable to make the most out of the system.

However, I'm optimistic and I think it's getting better. For example, I was pleasantly surprised how GNOME seamlessly re-scales the interface after connecting/disconnecting a non-HiDPI monitor. Suspend also works without a hitch!