[SRU][R][Unstable][PATCH 00/12] Resolute real-time patchset: 7.0-rc1-rt1

[Kevin Becker]

BugLink: https://bugs.launchpad.net/bugs/2143181

== SRU Justification ==

[Impact]

Starting in resolute, the patches from the PREEMPT_RT patchset will be applied to generic so they can be inherited by derivative kernels and flavors that need real-time. This set of patches will be filtered to only ones that apply where we support real-time, including amd64 and arm64.

[Fix]

For kernel 7.0, the upstream PREEMPT_RT patchset 7.0-rc1-rt1 has been released. 

https://lore.kernel.org/linux-rt-users/20260225120502.XKhQxj1F@linutronix.de/T/

These patches will be applied to resolute:linux (but with CONFIG_PREEMPT_RT disabled there) and inherited by other kernels. These patches include the following:

UBUNTU: Real-time patchset 7.0-rc1-rt1
UBUNTU: SAUCE: sysfs: Add /sys/kernel/realtime entry
UBUNTU: SAUCE: Revert "drm/i915: Depend on !PREEMPT_RT."
UBUNTU: SAUCE: drm/i915: Consider RCU read section as atomic.
UBUNTU: SAUCE: drm/i915/guc: Consider also RCU depth in busy loop.
UBUNTU: SAUCE: drm/i915: Drop the irqs_disabled() check
UBUNTU: SAUCE: drm/i915/gt: Use spin_lock_irq() instead of local_irq_disable() + spin_lock()
UBUNTU: SAUCE: drm/i915: Disable tracing points on PREEMPT_RT
UBUNTU: SAUCE: drm/i915: Don't disable interrupts on PREEMPT_RT during atomic updates
UBUNTU: SAUCE: drm/i915: Use preempt_disable/enable_rt() where recommended
UBUNTU: SAUCE: Reapply "serial: 8250: Revert "drop lockdep annotation from serial8250_clear_IER()""
UBUNTU: SAUCE: Reapply "serial: 8250: Switch to nbcon console"

[Test Case]

Compile and boot test

[Where things could go wrong]

These patches primarily apply to the 8250 serial driver and Intel i915 drm driver, so they may cause minor performance differences in these drivers even when PREEMPT_RT is disabled.

Clark Williams (1):
  UBUNTU: SAUCE: sysfs: Add /sys/kernel/realtime entry

Kevin Becker (1):
  UBUNTU: Real-time patchset 7.0-rc1-rt1

Mike Galbraith (2):
  UBUNTU: SAUCE: drm/i915: Use preempt_disable/enable_rt() where
    recommended
  UBUNTU: SAUCE: drm/i915: Don't disable interrupts on PREEMPT_RT during
    atomic updates

Sebastian Andrzej Siewior (8):
  UBUNTU: SAUCE: Reapply "serial: 8250: Switch to nbcon console"
  UBUNTU: SAUCE: Reapply "serial: 8250: Revert "drop lockdep annotation
    from serial8250_clear_IER()""
  UBUNTU: SAUCE: drm/i915: Disable tracing points on PREEMPT_RT
  UBUNTU: SAUCE: drm/i915/gt: Use spin_lock_irq() instead of
    local_irq_disable() + spin_lock()
  UBUNTU: SAUCE: drm/i915: Drop the irqs_disabled() check
  UBUNTU: SAUCE: drm/i915/guc: Consider also RCU depth in busy loop.
  UBUNTU: SAUCE: drm/i915: Consider RCU read section as atomic.
  UBUNTU: SAUCE: Revert "drm/i915: Depend on !PREEMPT_RT."

 debian.master/upstream-realtime               |   4 +
 drivers/gpu/drm/i915/Kconfig                  |   1 -
 drivers/gpu/drm/i915/display/intel_crtc.c     |   9 +-
 drivers/gpu/drm/i915/display/intel_cursor.c   |   9 +-
 .../drm/i915/display/intel_display_trace.h    |   4 +
 drivers/gpu/drm/i915/display/intel_vblank.c   |  50 +++--
 drivers/gpu/drm/i915/gt/intel_engine_cs.c     |   2 +-
 .../drm/i915/gt/intel_execlists_submission.c  |  17 +-
 drivers/gpu/drm/i915/gt/uc/intel_guc.h        |   2 +-
 drivers/gpu/drm/i915/i915_request.c           |   2 -
 drivers/gpu/drm/i915/i915_trace.h             |   4 +
 drivers/gpu/drm/i915/intel_uncore_trace.h     |   4 +
 drivers/tty/serial/8250/8250_core.c           |  35 +++-
 drivers/tty/serial/8250/8250_port.c           | 183 ++++++++++++++----
 include/linux/serial_8250.h                   |  13 +-
 kernel/ksysfs.c                               |  12 ++
 16 files changed, 275 insertions(+), 76 deletions(-)
 create mode 100644 debian.master/upstream-realtime

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2.43.0