From 9d54dfea168996d4f26e39f8cf6d1e2ea818f483 Mon Sep 17 00:00:00 2001
From: Eric Naim <dnaim@cachyos.org>
Date: Sun, 12 Jan 2025 19:01:13 +0700
Subject: [PATCH] rt
Signed-off-by: Eric Naim <dnaim@cachyos.org>
---
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 ++++++++++++++-----
.../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/i915_utils.h | 9 +++-
kernel/ksysfs.c | 12 +++++
11 files changed, 82 insertions(+), 36 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 a2c528d707f4..1a5035be9eb4 100644
--- a/drivers/gpu/drm/i915/display/intel_crtc.c
+++ b/drivers/gpu/drm/i915/display/intel_crtc.c
@@ -555,7 +555,8 @@ 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;
@@ -573,7 +574,8 @@ 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)
@@ -715,7 +717,8 @@ void intel_pipe_update_end(struct intel_atomic_state *state,
*/
intel_vrr_send_push(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 9ba77970dab7..70db13c8ccb1 100644
--- a/drivers/gpu/drm/i915/display/intel_cursor.c
+++ b/drivers/gpu/drm/i915/display/intel_cursor.c
@@ -901,13 +901,15 @@ 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) {
@@ -917,7 +919,8 @@ 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 9bd8f1e505b0..f2c9e7b3ab94 100644
--- a/drivers/gpu/drm/i915/display/intel_display_trace.h
+++ b/drivers/gpu/drm/i915/display/intel_display_trace.h
@@ -9,6 +9,10 @@
#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 <linux/string.h>
#include <linux/string_helpers.h>
#include <linux/types.h>
diff --git a/drivers/gpu/drm/i915/display/intel_vblank.c b/drivers/gpu/drm/i915/display/intel_vblank.c
index a95fb3349eba..d0995cbb0457 100644
--- a/drivers/gpu/drm/i915/display/intel_vblank.c
+++ b/drivers/gpu/drm/i915/display/intel_vblank.c
@@ -309,6 +309,20 @@ 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)
{
@@ -317,6 +331,17 @@ 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,
@@ -353,10 +378,10 @@ 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)
@@ -420,10 +445,10 @@ 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
@@ -461,13 +486,11 @@ 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;
}
@@ -689,11 +712,13 @@ 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_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
index 72090f52fb85..1c6bb872de1a 100644
--- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
+++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
@@ -1303,7 +1303,7 @@ 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
@@ -1403,7 +1403,7 @@ 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;
}
}
@@ -1429,7 +1429,7 @@ 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 */
}
@@ -1591,7 +1591,7 @@ 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
@@ -1617,13 +1617,6 @@ 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);
@@ -2478,7 +2471,7 @@ 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 57b903132776..ff213b79ba83 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 8f62cfa23fb7..d8b8ce3a6602 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -609,7 +609,6 @@ bool __i915_request_submit(struct i915_request *request)
RQ_TRACE(request, "\n");
- GEM_BUG_ON(!irqs_disabled());
lockdep_assert_held(&engine->sched_engine->lock);
/*
@@ -718,7 +717,6 @@ 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 09d89bdf82f4..4250340508a0 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 <linux/stringify.h>
#include <linux/types.h>
#include <linux/tracepoint.h>
diff --git a/drivers/gpu/drm/i915/i915_utils.h b/drivers/gpu/drm/i915/i915_utils.h
index 609214231ffc..91b3e55c389e 100644
--- a/drivers/gpu/drm/i915/i915_utils.h
+++ b/drivers/gpu/drm/i915/i915_utils.h
@@ -269,8 +269,13 @@ wait_remaining_ms_from_jiffies(unsigned long timestamp_jiffies, int to_wait_ms)
(Wmax))
#define wait_for(COND, MS) _wait_for((COND), (MS) * 1000, 10, 1000)
-/* If CONFIG_PREEMPT_COUNT is disabled, in_atomic() always reports false. */
-#if IS_ENABLED(CONFIG_DRM_I915_DEBUG) && IS_ENABLED(CONFIG_PREEMPT_COUNT)
+/*
+ * If CONFIG_PREEMPT_COUNT is disabled, in_atomic() always reports false.
+ * On PREEMPT_RT the context isn't becoming atomic because it is used in an
+ * interrupt handler or because a spinlock_t is acquired. This leads to
+ * warnings which don't occur otherwise and therefore the check is disabled.
+ */
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG) && IS_ENABLED(CONFIG_PREEMPT_COUNT) && !defined(CONFIG_PREEMPT_RT)
# define _WAIT_FOR_ATOMIC_CHECK(ATOMIC) WARN_ON_ONCE((ATOMIC) && !in_atomic())
#else
# define _WAIT_FOR_ATOMIC_CHECK(ATOMIC) do { } while (0)
diff --git a/kernel/ksysfs.c b/kernel/ksysfs.c
index 1bab21b4718f..8d3bee77cacc 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)
@@ -285,6 +294,9 @@ 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
};
--
2.48.0