diff options
Diffstat (limited to 'debian/patches-rt/0002-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch')
| -rw-r--r-- | debian/patches-rt/0002-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/debian/patches-rt/0002-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch b/debian/patches-rt/0002-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch new file mode 100644 index 0000000000..c4f8ef9737 --- /dev/null +++ b/debian/patches-rt/0002-drm-i915-Don-t-disable-interrupts-on-PREEMPT_RT-duri.patch @@ -0,0 +1,119 @@ +From: Mike Galbraith <umgwanakikbuti@gmail.com> +Date: Sat, 27 Feb 2016 09:01:42 +0100 +Subject: [PATCH 2/8] drm/i915: Don't disable interrupts on PREEMPT_RT during + atomic updates +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.10/older/patches-6.10.2-rt14.tar.xz + +Commit + 8d7849db3eab7 ("drm/i915: Make sprite updates atomic") + +started disabling interrupts across atomic updates. This breaks on PREEMPT_RT +because within this section the code attempt to acquire spinlock_t locks which +are sleeping locks on PREEMPT_RT. + +According to the comment the interrupts are disabled to avoid random delays and +not required for protection or synchronisation. +If this needs to happen with disabled interrupts on PREEMPT_RT, and the +whole section is restricted to register access then all sleeping locks +need to be acquired before interrupts are disabled and some function +maybe moved after enabling interrupts again. +This includes: +- prepare_to_wait() + finish_wait() due its wake queue. +- drm_crtc_vblank_put() -> vblank_disable_fn() drm_device::vbl_lock. +- skl_pfit_enable(), intel_update_plane(), vlv_atomic_update_fifo() and + maybe others due to intel_uncore::lock +- drm_crtc_arm_vblank_event() due to drm_device::event_lock and + drm_device::vblank_time_lock. + +Don't disable interrupts on PREEMPT_RT during atomic updates. + +[bigeasy: drop local locks, commit message] + +Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + drivers/gpu/drm/i915/display/intel_crtc.c | 9 ++++++--- + drivers/gpu/drm/i915/display/intel_cursor.c | 9 ++++++--- + drivers/gpu/drm/i915/display/intel_vblank.c | 6 ++++-- + 3 files changed, 16 insertions(+), 8 deletions(-) + +--- a/drivers/gpu/drm/i915/display/intel_crtc.c ++++ b/drivers/gpu/drm/i915/display/intel_crtc.c +@@ -521,7 +521,8 @@ void intel_pipe_update_start(struct inte + */ + 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; +@@ -539,7 +540,8 @@ void intel_pipe_update_start(struct inte + return; + + irq_disable: +- local_irq_disable(); ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) ++ local_irq_disable(); + } + + #if IS_ENABLED(CONFIG_DRM_I915_DEBUG_VBLANK_EVADE) +@@ -668,7 +670,8 @@ void intel_pipe_update_end(struct intel_ + */ + 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; +--- a/drivers/gpu/drm/i915/display/intel_cursor.c ++++ b/drivers/gpu/drm/i915/display/intel_cursor.c +@@ -895,13 +895,15 @@ intel_legacy_cursor_update(struct drm_pl + */ + 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) { +@@ -911,7 +913,8 @@ intel_legacy_cursor_update(struct drm_pl + intel_plane_disable_arm(plane, crtc_state); + } + +- local_irq_enable(); ++ if (!IS_ENABLED(CONFIG_PREEMPT_RT)) ++ local_irq_enable(); + + intel_psr_unlock(crtc_state); + +--- a/drivers/gpu/drm/i915/display/intel_vblank.c ++++ b/drivers/gpu/drm/i915/display/intel_vblank.c +@@ -705,11 +705,13 @@ int intel_vblank_evade(struct intel_vbla + 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); |