From a0de616b608f73ad6b9390d03c52a81dd4a0ec55 Mon Sep 17 00:00:00 2001 From: Eric Naim Date: Tue, 2 Dec 2025 02:41:38 +0800 Subject: [PATCH] rt-i915 Signed-off-by: Eric Naim --- 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 | 49 ++++++++++++++----- 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 ++ kernel/ksysfs.c | 12 +++++ 12 files changed, 80 insertions(+), 35 deletions(-) diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig index 5e939004b646..40a9234e6e5d 100644 --- a/drivers/gpu/drm/i915/Kconfig +++ b/drivers/gpu/drm/i915/Kconfig @@ -3,7 +3,6 @@ config DRM_I915 tristate "Intel 8xx/9xx/G3x/G4x/HD Graphics" depends on DRM depends on X86 && PCI - depends on !PREEMPT_RT select INTEL_GTT if X86 select INTERVAL_TREE # we need shmfs for the swappable backing store, and in particular diff --git a/drivers/gpu/drm/i915/display/intel_crtc.c b/drivers/gpu/drm/i915/display/intel_crtc.c index a187db6df2d3..dbdc4d9b2a33 100644 --- a/drivers/gpu/drm/i915/display/intel_crtc.c +++ b/drivers/gpu/drm/i915/display/intel_crtc.c @@ -562,7 +562,8 @@ void intel_pipe_update_start(struct intel_atomic_state *state, */ intel_psr_wait_for_idle_locked(new_crtc_state); - local_irq_disable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_disable(); crtc->debug.min_vbl = evade.min; crtc->debug.max_vbl = evade.max; @@ -580,7 +581,8 @@ void intel_pipe_update_start(struct intel_atomic_state *state, return; irq_disable: - local_irq_disable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_disable(); } #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_VBLANK_EVADE) @@ -726,7 +728,8 @@ void intel_pipe_update_end(struct intel_atomic_state *state, if (!state->base.legacy_cursor_update) intel_vrr_send_push(NULL, new_crtc_state); - local_irq_enable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_enable(); if (intel_vgpu_active(dev_priv)) goto out; diff --git a/drivers/gpu/drm/i915/display/intel_cursor.c b/drivers/gpu/drm/i915/display/intel_cursor.c index d4d181f9dca5..58f2f074aff2 100644 --- a/drivers/gpu/drm/i915/display/intel_cursor.c +++ b/drivers/gpu/drm/i915/display/intel_cursor.c @@ -919,13 +919,15 @@ intel_legacy_cursor_update(struct drm_plane *_plane, */ intel_psr_wait_for_idle_locked(crtc_state); - local_irq_disable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_disable(); intel_vblank_evade(&evade); drm_crtc_vblank_put(&crtc->base); } else { - local_irq_disable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_disable(); } if (new_plane_state->uapi.visible) { @@ -935,7 +937,8 @@ intel_legacy_cursor_update(struct drm_plane *_plane, intel_plane_disable_arm(NULL, plane, crtc_state); } - local_irq_enable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_enable(); intel_psr_unlock(crtc_state); diff --git a/drivers/gpu/drm/i915/display/intel_display_trace.h b/drivers/gpu/drm/i915/display/intel_display_trace.h index 27ebc32cb61a..a519d94700c3 100644 --- a/drivers/gpu/drm/i915/display/intel_display_trace.h +++ b/drivers/gpu/drm/i915/display/intel_display_trace.h @@ -13,6 +13,10 @@ #if !defined(__INTEL_DISPLAY_TRACE_H__) || defined(TRACE_HEADER_MULTI_READ) #define __INTEL_DISPLAY_TRACE_H__ +#if defined(CONFIG_PREEMPT_RT) && !defined(NOTRACE) +#define NOTRACE +#endif + #include #include #include diff --git a/drivers/gpu/drm/i915/display/intel_vblank.c b/drivers/gpu/drm/i915/display/intel_vblank.c index c15234c1d96e..590a079f926b 100644 --- a/drivers/gpu/drm/i915/display/intel_vblank.c +++ b/drivers/gpu/drm/i915/display/intel_vblank.c @@ -315,6 +315,20 @@ static void intel_vblank_section_exit(struct intel_display *display) struct drm_i915_private *i915 = to_i915(display->drm); spin_unlock(&i915->uncore.lock); } + +static void intel_vblank_section_enter_irqf(struct intel_display *display, unsigned long *flags) + __acquires(i915->uncore.lock) +{ + struct drm_i915_private *i915 = to_i915(display->drm); + spin_lock_irqsave(&i915->uncore.lock, *flags); +} + +static void intel_vblank_section_exit_irqf(struct intel_display *display, unsigned long flags) + __releases(i915->uncore.lock) +{ + struct drm_i915_private *i915 = to_i915(display->drm); + spin_unlock_irqrestore(&i915->uncore.lock, flags); +} #else static void intel_vblank_section_enter(struct intel_display *display) { @@ -323,6 +337,17 @@ static void intel_vblank_section_enter(struct intel_display *display) static void intel_vblank_section_exit(struct intel_display *display) { } + +static void intel_vblank_section_enter_irqf(struct intel_display *display, unsigned long *flags) +{ + *flags = 0; +} + +static void intel_vblank_section_exit_irqf(struct intel_display *display, unsigned long flags) +{ + if (flags) + return; +} #endif static bool i915_get_crtc_scanoutpos(struct drm_crtc *_crtc, @@ -359,10 +384,10 @@ static bool i915_get_crtc_scanoutpos(struct drm_crtc *_crtc, * timing critical raw register reads, potentially with * preemption disabled, so the following code must not block. */ - local_irq_save(irqflags); - intel_vblank_section_enter(display); + intel_vblank_section_enter_irqf(display, &irqflags); - /* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */ + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_disable(); /* Get optional system timestamp before query. */ if (stime) @@ -426,10 +451,10 @@ static bool i915_get_crtc_scanoutpos(struct drm_crtc *_crtc, if (etime) *etime = ktime_get(); - /* preempt_enable_rt() should go right here in PREEMPT_RT patchset. */ + if (IS_ENABLED(CONFIG_PREEMPT_RT)) + preempt_enable(); - intel_vblank_section_exit(display); - local_irq_restore(irqflags); + intel_vblank_section_exit_irqf(display, irqflags); /* * While in vblank, position will be negative @@ -467,13 +492,11 @@ int intel_get_crtc_scanline(struct intel_crtc *crtc) unsigned long irqflags; int position; - local_irq_save(irqflags); - intel_vblank_section_enter(display); + intel_vblank_section_enter_irqf(display, &irqflags); position = __intel_get_crtc_scanline(crtc); - intel_vblank_section_exit(display); - local_irq_restore(irqflags); + intel_vblank_section_exit_irqf(display, irqflags); return position; } @@ -738,11 +761,13 @@ int intel_vblank_evade(struct intel_vblank_evade_ctx *evade) break; } - local_irq_enable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_enable(); timeout = schedule_timeout(timeout); - local_irq_disable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_disable(); } finish_wait(wq, &wait); diff --git a/drivers/gpu/drm/i915/gt/intel_engine_cs.c b/drivers/gpu/drm/i915/gt/intel_engine_cs.c index b721bbd23356..f5a6143ea8a2 100644 --- a/drivers/gpu/drm/i915/gt/intel_engine_cs.c +++ b/drivers/gpu/drm/i915/gt/intel_engine_cs.c @@ -1609,7 +1609,7 @@ u64 intel_engine_get_last_batch_head(const struct intel_engine_cs *engine) static unsigned long stop_timeout(const struct intel_engine_cs *engine) { - if (in_atomic() || irqs_disabled()) /* inside atomic preempt-reset? */ + if (in_atomic() || irqs_disabled() || rcu_preempt_depth()) /* inside atomic preempt-reset? */ return 0; /* diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c index 7f389cb0bde4..607c9a7b3a0a 100644 --- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c +++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c @@ -1298,7 +1298,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine) * and context switches) submission. */ - spin_lock(&sched_engine->lock); + spin_lock_irq(&sched_engine->lock); /* * If the queue is higher priority than the last @@ -1398,7 +1398,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine) * Even if ELSP[1] is occupied and not worthy * of timeslices, our queue might be. */ - spin_unlock(&sched_engine->lock); + spin_unlock_irq(&sched_engine->lock); return; } } @@ -1424,7 +1424,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine) if (last && !can_merge_rq(last, rq)) { spin_unlock(&ve->base.sched_engine->lock); - spin_unlock(&engine->sched_engine->lock); + spin_unlock_irq(&engine->sched_engine->lock); return; /* leave this for another sibling */ } @@ -1586,7 +1586,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine) */ sched_engine->queue_priority_hint = queue_prio(sched_engine); i915_sched_engine_reset_on_empty(sched_engine); - spin_unlock(&sched_engine->lock); + spin_unlock_irq(&sched_engine->lock); /* * We can skip poking the HW if we ended up with exactly the same set @@ -1612,13 +1612,6 @@ static void execlists_dequeue(struct intel_engine_cs *engine) } } -static void execlists_dequeue_irq(struct intel_engine_cs *engine) -{ - local_irq_disable(); /* Suspend interrupts across request submission */ - execlists_dequeue(engine); - local_irq_enable(); /* flush irq_work (e.g. breadcrumb enabling) */ -} - static void clear_ports(struct i915_request **ports, int count) { memset_p((void **)ports, NULL, count); @@ -2473,7 +2466,7 @@ static void execlists_submission_tasklet(struct tasklet_struct *t) } if (!engine->execlists.pending[0]) { - execlists_dequeue_irq(engine); + execlists_dequeue(engine); start_timeslice(engine); } diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h index 053780f562c1..b25fa8f4dc4b 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h @@ -362,7 +362,7 @@ static inline int intel_guc_send_busy_loop(struct intel_guc *guc, { int err; unsigned int sleep_period_ms = 1; - bool not_atomic = !in_atomic() && !irqs_disabled(); + bool not_atomic = !in_atomic() && !irqs_disabled() && !rcu_preempt_depth(); /* * FIXME: Have caller pass in if we are in an atomic context to avoid diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c index b9a2b2194c8f..e24798e4b44e 100644 --- a/drivers/gpu/drm/i915/i915_request.c +++ b/drivers/gpu/drm/i915/i915_request.c @@ -608,7 +608,6 @@ bool __i915_request_submit(struct i915_request *request) RQ_TRACE(request, "\n"); - GEM_BUG_ON(!irqs_disabled()); lockdep_assert_held(&engine->sched_engine->lock); /* @@ -717,7 +716,6 @@ void __i915_request_unsubmit(struct i915_request *request) */ RQ_TRACE(request, "\n"); - GEM_BUG_ON(!irqs_disabled()); lockdep_assert_held(&engine->sched_engine->lock); /* diff --git a/drivers/gpu/drm/i915/i915_trace.h b/drivers/gpu/drm/i915/i915_trace.h index 7ed41ce9b708..6b87ef6005c6 100644 --- a/drivers/gpu/drm/i915/i915_trace.h +++ b/drivers/gpu/drm/i915/i915_trace.h @@ -6,6 +6,10 @@ #if !defined(_I915_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ) #define _I915_TRACE_H_ +#if defined(CONFIG_PREEMPT_RT) && !defined(NOTRACE) +#define NOTRACE +#endif + #include #include #include diff --git a/drivers/gpu/drm/i915/intel_uncore_trace.h b/drivers/gpu/drm/i915/intel_uncore_trace.h index f13ff71edf2d..3c67e267fb60 100644 --- a/drivers/gpu/drm/i915/intel_uncore_trace.h +++ b/drivers/gpu/drm/i915/intel_uncore_trace.h @@ -7,6 +7,10 @@ #if !defined(__INTEL_UNCORE_TRACE_H__) || defined(TRACE_HEADER_MULTI_READ) #define __INTEL_UNCORE_TRACE_H__ +#if defined(CONFIG_PREEMPT_RT) && !defined(NOTRACE) +#define NOTRACE +#endif + #include "i915_reg_defs.h" #include diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c index eefb67d9883c..20ac8a5ac27d 100644 --- a/kernel/ksysfs.c +++ b/kernel/ksysfs.c @@ -188,6 +188,15 @@ KERNEL_ATTR_RO(crash_elfcorehdr_size); #endif /* CONFIG_VMCORE_INFO */ +#if defined(CONFIG_PREEMPT_RT) +static ssize_t realtime_show(struct kobject *kobj, + struct kobj_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", 1); +} +KERNEL_ATTR_RO(realtime); +#endif + /* whether file capabilities are enabled */ static ssize_t fscaps_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) @@ -271,6 +280,9 @@ static struct attribute * kernel_attrs[] = { #ifndef CONFIG_TINY_RCU &rcu_expedited_attr.attr, &rcu_normal_attr.attr, +#endif +#ifdef CONFIG_PREEMPT_RT + &realtime_attr.attr, #endif NULL }; -- 2.52.0