On Mon, Jan 08, 2024 at 10:31:07AM +0200, Hogander, Jouni wrote: > On Thu, 2024-01-04 at 10:30 +0200, Imre Deak wrote: > > An unexpected modeset or connector detection by a user (user space > > or FB console) during the initialization/shutdown sequence is > > possible either via a hotplug IRQ handling work or via the connector > > sysfs (status/detect) interface. These modesets/detections should be > > prevented by disabling/flushing all related hotplug handling work > > and unregistering the interfaces that can start them at the > > beginning of the shutdown sequence. Some of this - disabling all > > related intel_hotplug work - will be done by the next patch, but > > others - for instance disabling the MST hotplug works - require a > > bigger rework. > > > > It makes sense - for diagnostic purpose, even with all the above > > work and interface disabled - to detect and reject any such user > > access. This patch does that for modeset accesses and a follow-up > > patch for connector detection. > > > > After the display is disabled during the shutdown sequence, no > > modeset should happen so it's disabled for both users and the > > shutdown thread. > > Can you please explain in commit message why > intel_display_driver_disable_user_access and > intel_display_driver_resume_access are allowing modeset for "current" > process? Is it ok if I add the following instead of the last paragraph?: """ During driver loading/unloading/system suspend/shutdown and during system resume after calling intel_display_driver_disable_user_access() or intel_display_driver_resume_access() correspondigly, the current thread is allowed to modeset (as this thread requires to do an initial/restoring modeset or a disabling modeset), other threads (the user threads) are not allowed to modeset. During driver loading/system resume after calling intel_display_driver_enable_user_access() all threads are allowed to modeset. During driver unloading/system suspend/shutdown after calling intel_display_driver_suspend_access() no threads are allowed to modeset (as the HW got disabled and should stay in this state). """ > > BR, > > Jouni Högander > > > > > Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> > > --- > > drivers/gpu/drm/i915/display/intel_display.c | 3 + > > .../gpu/drm/i915/display/intel_display_core.h | 7 ++ > > .../drm/i915/display/intel_display_driver.c | 74 > > +++++++++++++++++++ > > .../drm/i915/display/intel_display_driver.h | 6 ++ > > drivers/gpu/drm/i915/i915_driver.c | 16 +++- > > 5 files changed, 104 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/display/intel_display.c > > b/drivers/gpu/drm/i915/display/intel_display.c > > index 927d124457b61..31a6a82c12616 100644 > > --- a/drivers/gpu/drm/i915/display/intel_display.c > > +++ b/drivers/gpu/drm/i915/display/intel_display.c > > @@ -6310,6 +6310,9 @@ int intel_atomic_check(struct drm_device *dev, > > int ret, i; > > bool any_ms = false; > > > > + if (!intel_display_driver_check_access(dev_priv)) > > + return -ENODEV; > > + > > for_each_oldnew_intel_crtc_in_state(state, crtc, > > old_crtc_state, > > new_crtc_state, i) { > > /* > > diff --git a/drivers/gpu/drm/i915/display/intel_display_core.h > > b/drivers/gpu/drm/i915/display/intel_display_core.h > > index 47297ed858223..0b130ca9e6698 100644 > > --- a/drivers/gpu/drm/i915/display/intel_display_core.h > > +++ b/drivers/gpu/drm/i915/display/intel_display_core.h > > @@ -28,6 +28,8 @@ > > #include "intel_opregion.h" > > #include "intel_wm_types.h" > > > > +struct task_struct; > > + > > struct drm_i915_private; > > struct drm_property; > > struct drm_property_blob; > > @@ -298,6 +300,11 @@ struct intel_display { > > const struct intel_audio_funcs *audio; > > } funcs; > > > > + struct { > > + bool any_task_allowed; > > + struct task_struct *allowed_task; > > + } access; > > + > > struct { > > /* backlight registers and fields in struct > > intel_panel */ > > struct mutex lock; > > diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.c > > b/drivers/gpu/drm/i915/display/intel_display_driver.c > > index 1974f2394a518..b2441ab9822c2 100644 > > --- a/drivers/gpu/drm/i915/display/intel_display_driver.c > > +++ b/drivers/gpu/drm/i915/display/intel_display_driver.c > > @@ -45,6 +45,7 @@ > > #include "intel_hdcp.h" > > #include "intel_hotplug.h" > > #include "intel_hti.h" > > +#include "intel_modeset_lock.h" > > #include "intel_modeset_setup.h" > > #include "intel_opregion.h" > > #include "intel_overlay.h" > > @@ -276,6 +277,71 @@ int intel_display_driver_probe_noirq(struct > > drm_i915_private *i915) > > return ret; > > } > > > > +static void set_display_access(struct drm_i915_private *i915, > > + bool any_task_allowed, > > + struct task_struct *allowed_task) > > +{ > > + struct drm_modeset_acquire_ctx ctx; > > + int err; > > + > > + intel_modeset_lock_ctx_retry(&ctx, NULL, 0, err) { > > + err = drm_modeset_lock_all_ctx(&i915->drm, &ctx); > > + if (err) > > + continue; > > + > > + i915->display.access.any_task_allowed = > > any_task_allowed; > > + i915->display.access.allowed_task = allowed_task; > > + } > > + > > + drm_WARN_ON(&i915->drm, err); > > +} > > + > > +void intel_display_driver_enable_user_access(struct drm_i915_private > > *i915) > > +{ > > + set_display_access(i915, true, NULL); > > +} > > + > > +void intel_display_driver_disable_user_access(struct > > drm_i915_private *i915) > > +{ > > + set_display_access(i915, false, current); > > +} > > + > > +void intel_display_driver_suspend_access(struct drm_i915_private > > *i915) > > +{ > > + set_display_access(i915, false, NULL); > > +} > > + > > +void intel_display_driver_resume_access(struct drm_i915_private > > *i915) > > +{ > > + set_display_access(i915, false, current); > > +} > > + > > +bool intel_display_driver_check_access(struct drm_i915_private > > *i915) > > +{ > > + char comm[TASK_COMM_LEN]; > > + char current_task[TASK_COMM_LEN + 16]; > > + char allowed_task[TASK_COMM_LEN + 16] = "none"; > > + > > + if (i915->display.access.any_task_allowed || > > + i915->display.access.allowed_task == current) > > + return true; > > + > > + snprintf(current_task, sizeof(current_task), "%s[%d]", > > + get_task_comm(comm, current), > > + task_pid_vnr(current)); > > + > > + if (i915->display.access.allowed_task) > > + snprintf(allowed_task, sizeof(allowed_task), > > "%s[%d]", > > + get_task_comm(comm, i915- > > >display.access.allowed_task), > > + task_pid_vnr(i915- > > >display.access.allowed_task)); > > + > > + drm_dbg_kms(&i915->drm, > > + "Reject display access from task %s (allowed to > > %s)\n", > > + current_task, allowed_task); > > + > > + return false; > > +} > > + > > /* part #2: call after irq install, but before gem init */ > > int intel_display_driver_probe_nogem(struct drm_i915_private *i915) > > { > > @@ -326,6 +392,8 @@ int intel_display_driver_probe_nogem(struct > > drm_i915_private *i915) > > intel_vga_disable(i915); > > intel_setup_outputs(i915); > > > > + intel_display_driver_disable_user_access(i915); > > + > > drm_modeset_lock_all(dev); > > intel_modeset_setup_hw_state(i915, dev- > > >mode_config.acquire_ctx); > > intel_acpi_assign_connector_fwnodes(i915); > > @@ -393,6 +461,8 @@ void intel_display_driver_register(struct > > drm_i915_private *i915) > > > > intel_audio_init(i915); > > > > + intel_display_driver_enable_user_access(i915); > > + > > intel_display_debugfs_register(i915); > > > > /* > > @@ -440,6 +510,8 @@ void intel_display_driver_remove_noirq(struct > > drm_i915_private *i915) > > if (!HAS_DISPLAY(i915)) > > return; > > > > + intel_display_driver_suspend_access(i915); > > + > > /* > > * Due to the hpd irq storm handling the hotplug work can re- > > arm the > > * poll handlers. Hence disable polling after hpd handling is > > shut down. > > @@ -493,6 +565,8 @@ void intel_display_driver_unregister(struct > > drm_i915_private *i915) > > */ > > drm_kms_helper_poll_fini(&i915->drm); > > > > + intel_display_driver_disable_user_access(i915); > > + > > intel_audio_deinit(i915); > > > > drm_atomic_helper_shutdown(&i915->drm); > > diff --git a/drivers/gpu/drm/i915/display/intel_display_driver.h > > b/drivers/gpu/drm/i915/display/intel_display_driver.h > > index c276a58ee3293..42cc4af6d3fd5 100644 > > --- a/drivers/gpu/drm/i915/display/intel_display_driver.h > > +++ b/drivers/gpu/drm/i915/display/intel_display_driver.h > > @@ -32,5 +32,11 @@ int __intel_display_driver_resume(struct > > drm_i915_private *i915, > > struct drm_atomic_state *state, > > struct drm_modeset_acquire_ctx > > *ctx); > > > > +void intel_display_driver_enable_user_access(struct drm_i915_private > > *i915); > > +void intel_display_driver_disable_user_access(struct > > drm_i915_private *i915); > > +void intel_display_driver_suspend_access(struct drm_i915_private > > *i915); > > +void intel_display_driver_resume_access(struct drm_i915_private > > *i915); > > +bool intel_display_driver_check_access(struct drm_i915_private > > *i915); > > + > > #endif /* __INTEL_DISPLAY_DRIVER_H__ */ > > > > diff --git a/drivers/gpu/drm/i915/i915_driver.c > > b/drivers/gpu/drm/i915/i915_driver.c > > index 166476948c896..068ca48e05323 100644 > > --- a/drivers/gpu/drm/i915/i915_driver.c > > +++ b/drivers/gpu/drm/i915/i915_driver.c > > @@ -1006,6 +1006,7 @@ void i915_driver_shutdown(struct > > drm_i915_private *i915) > > intel_fbdev_set_suspend(&i915->drm, FBINFO_STATE_SUSPENDED, > > true); > > if (HAS_DISPLAY(i915)) { > > drm_kms_helper_poll_disable(&i915->drm); > > + intel_display_driver_disable_user_access(i915); > > > > drm_atomic_helper_shutdown(&i915->drm); > > } > > @@ -1015,6 +1016,8 @@ void i915_driver_shutdown(struct > > drm_i915_private *i915) > > intel_runtime_pm_disable_interrupts(i915); > > intel_hpd_cancel_work(i915); > > > > + intel_display_driver_suspend_access(i915); > > + > > intel_suspend_encoders(i915); > > intel_shutdown_encoders(i915); > > > > @@ -1082,8 +1085,10 @@ static int i915_drm_suspend(struct drm_device > > *dev) > > * properly. */ > > intel_power_domains_disable(dev_priv); > > intel_fbdev_set_suspend(dev, FBINFO_STATE_SUSPENDED, true); > > - if (HAS_DISPLAY(dev_priv)) > > + if (HAS_DISPLAY(dev_priv)) { > > drm_kms_helper_poll_disable(dev); > > + intel_display_driver_disable_user_access(dev_priv); > > + } > > > > pci_save_state(pdev); > > > > @@ -1094,6 +1099,8 @@ static int i915_drm_suspend(struct drm_device > > *dev) > > intel_runtime_pm_disable_interrupts(dev_priv); > > intel_hpd_cancel_work(dev_priv); > > > > + intel_display_driver_suspend_access(dev_priv); > > + > > intel_suspend_encoders(dev_priv); > > > > /* Must be called before GGTT is suspended. */ > > @@ -1243,14 +1250,19 @@ static int i915_drm_resume(struct drm_device > > *dev) > > intel_display_driver_init_hw(dev_priv); > > > > intel_clock_gating_init(dev_priv); > > + > > + intel_display_driver_resume_access(dev_priv); > > + > > intel_hpd_init(dev_priv); > > > > /* MST sideband requires HPD interrupts enabled */ > > intel_dp_mst_resume(dev_priv); > > intel_display_driver_resume(dev_priv); > > > > - if (HAS_DISPLAY(dev_priv)) > > + if (HAS_DISPLAY(dev_priv)) { > > + intel_display_driver_enable_user_access(dev_priv); > > drm_kms_helper_poll_enable(dev); > > + } > > intel_hpd_poll_disable(dev_priv); > > > > intel_opregion_resume(dev_priv); >