With the Linux 6.15-rc6 kernel release due out on Sunday, we're hitting the transition point where the focus on DRM kernel graphics drivers for Linux 6.16 is shifting from feature work to bug-fixing ahead of this next merge window. As such sent out today were drm-misc-next and drm-intel-gt-next pull requests focused on preparing various kernel graphics/display driver fixes for the new code coming to Linux 6.16. The Intel pull request today even contains a fix for aging Intel Haswell graphics.

While Intel Haswell era graphics have long been discontinued on the Microsoft Windows side from active driver support, there remains the mainline support within the i915 kernel driver for the old Haswell "HSW" era graphics.

Coming for Linux 6.16 is adding a 20ms delay to the code path for engine reset to improve robustness on the old integrated graphics. The patch from Nitin Gote explains:

"Sometimes engine reset fails because the engine resumes from an incorrect RING_HEAD. Engine head failed to set to zero even after writing into it. This is a timing issue and we experimented different values and found out that 20ms delay works best based on testing.

So, add a 20ms delay to let engine resumes from correct RING_HEAD."

Thus fixing some engine reset issues for anyone still relying on an old Intel Haswell era system.

The other changes included in today's drm-intel-gt-next pull request for Linux 6.16 material includes:

"Driver Changes:

- Fix SLPC wait boosting reference counting to avoid getting stuck on non-boost
frequency on power saving profile on DG1/DG2 (Vinay)
- Add 20ms delay to engine reset for robustness on HSW (Nitin)
- Use proper sleeping functions for timeouts shorter than 20ms (Andi)
- Fix fence not released on early probe errors for HuC (Janusz)
- Remove const from struct i915_wa list allocation (Kees)
- Apply SPDX license format where missing and use single-line format (Andi)
- Whitespace fixes (Dan, Andi)
- Selftest improvements (Mikolaj, Badal, Sk,"

Separately, also sent out today was drm-misc-next with some final material for Linux 6.16 ahead of getting more into bug fixing:

"- Small fixes to appletbdrm, panthor, st7571-i2c, rockchip, renesas,
panic handler, gpusvm, vkms, panel timings.
- Add AUO B140QAN08.H, BOE NE140WUM-N6S, CSW MNE007QS3-8, BOE TD4320 panels.
- Convert rk3066_hdmi to bridge driver.
- Improve HPD on anx7625.
- Speed up loading tegra firmware, and other small fixes to tegra & host1x."

The Linux 6.16 merge window should be opening up around the end of May following the Linux v6.15 release tag.