drm/i915: Introduce better global state handling

Our current global state handling is pretty ad-hoc. Let's try to
make it better by imitating the standard drm core private object
approach.

The reason why we don't want to directly use the private objects
is locking; Each private object has its own lock so if we
introduce any global private objects we get serialized by that
single lock across all pipes. The global state apporoach instead
uses a read/write lock type of approach where each individual
crtc lock counts as a read lock, and grabbing all the crtc locks
allows one write access.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200120174728.21095-15-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 3c88d7d8c76498b72fed804fdb97780eb950114c..787ffe6698107bb28f67a1ec48e6c70b989811dd 100644 (file)
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -190,6 +190,7 @@ i915-y += \
        display/intel_fbc.o \
        display/intel_fifo_underrun.o \
        display/intel_frontbuffer.o \
+       display/intel_global_state.o \
        display/intel_hdcp.o \
        display/intel_hotplug.o \
        display/intel_lpe_audio.o \

diff --git a/drivers/gpu/drm/i915/display/intel_atomic.c b/drivers/gpu/drm/i915/display/intel_atomic.c
index 110cc58346f5946c4daec19e9267635036bcf9f7..476d0271de0a4b3bc39febc01b39a65e1d6ed1a2 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_atomic.c
+++ b/drivers/gpu/drm/i915/display/intel_atomic.c
@@ -37,6 +37,7 @@
 #include "intel_atomic.h"
 #include "intel_cdclk.h"
 #include "intel_display_types.h"
+#include "intel_global_state.h"
 #include "intel_hdcp.h"
 #include "intel_psr.h"
 #include "intel_sprite.h"
@@ -502,6 +503,7 @@ void intel_atomic_state_free(struct drm_atomic_state *_state)
        struct intel_atomic_state *state = to_intel_atomic_state(_state);
 
        drm_atomic_state_default_release(&state->base);
+       kfree(state->global_objs);
 
        i915_sw_fence_fini(&state->commit_ready);
 
@@ -513,6 +515,7 @@ void intel_atomic_state_clear(struct drm_atomic_state *s)
        struct intel_atomic_state *state = to_intel_atomic_state(s);
 
        drm_atomic_state_default_clear(&state->base);
+       intel_atomic_clear_global_state(state);
 
        state->dpll_set = state->modeset = false;
        state->global_state_changed = false;
@@ -532,7 +535,7 @@ intel_atomic_get_crtc_state(struct drm_atomic_state *state,
        return to_intel_crtc_state(crtc_state);
 }
 
-int intel_atomic_lock_global_state(struct intel_atomic_state *state)
+int _intel_atomic_lock_global_state(struct intel_atomic_state *state)
 {
        struct drm_i915_private *dev_priv = to_i915(state->base.dev);
        struct intel_crtc *crtc;
@@ -551,7 +554,7 @@ int intel_atomic_lock_global_state(struct intel_atomic_state *state)
        return 0;
 }
 
-int intel_atomic_serialize_global_state(struct intel_atomic_state *state)
+int _intel_atomic_serialize_global_state(struct intel_atomic_state *state)
 {
        struct drm_i915_private *dev_priv = to_i915(state->base.dev);
        struct intel_crtc *crtc;

diff --git a/drivers/gpu/drm/i915/display/intel_atomic.h b/drivers/gpu/drm/i915/display/intel_atomic.h
index 88133eea0a171b71353bb91e6a30289082d4584e..11146292b06f528391c7b40749b6f5ed97034aba 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_atomic.h
+++ b/drivers/gpu/drm/i915/display/intel_atomic.h
@@ -56,8 +56,8 @@ int intel_atomic_setup_scalers(struct drm_i915_private *dev_priv,
                               struct intel_crtc *intel_crtc,
                               struct intel_crtc_state *crtc_state);
 
-int intel_atomic_lock_global_state(struct intel_atomic_state *state);
+int _intel_atomic_lock_global_state(struct intel_atomic_state *state);
 
-int intel_atomic_serialize_global_state(struct intel_atomic_state *state);
+int _intel_atomic_serialize_global_state(struct intel_atomic_state *state);
 
 #endif /* __INTEL_ATOMIC_H__ */

diff --git a/drivers/gpu/drm/i915/display/intel_audio.c b/drivers/gpu/drm/i915/display/intel_audio.c
index fef292c915d404686d1ccc6856fb397b6b2c97ce..93bc403c3fa5ef3a9be1914be2b488dbdd7c2b45 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_audio.c
+++ b/drivers/gpu/drm/i915/display/intel_audio.c
@@ -829,7 +829,7 @@ retry:
                enable ? 2 * 96000 : 0;
 
        /* Protects dev_priv->cdclk.force_min_cdclk */
-       ret = intel_atomic_lock_global_state(to_intel_atomic_state(state));
+       ret = _intel_atomic_lock_global_state(to_intel_atomic_state(state));
        if (!ret)
                ret = drm_atomic_commit(state);
 

diff --git a/drivers/gpu/drm/i915/display/intel_cdclk.c b/drivers/gpu/drm/i915/display/intel_cdclk.c
index 3e0379db9b2bdca7d3f310f837ddb8bed18e0454..6368c0ef1e0f669093af9e9a9a39f696ccc85111 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/display/intel_cdclk.c
@@ -2080,7 +2080,7 @@ static int intel_compute_min_cdclk(struct intel_atomic_state *state)
 
                cdclk_state->min_cdclk[i] = min_cdclk;
 
-               ret = intel_atomic_lock_global_state(state);
+               ret = _intel_atomic_lock_global_state(state);
                if (ret)
                        return ret;
        }
@@ -2128,7 +2128,7 @@ static int bxt_compute_min_voltage_level(struct intel_atomic_state *state)
 
                cdclk_state->min_voltage_level[i] = min_voltage_level;
 
-               ret = intel_atomic_lock_global_state(state);
+               ret = _intel_atomic_lock_global_state(state);
                if (ret)
                        return ret;
        }
@@ -2403,12 +2403,12 @@ int intel_modeset_calc_cdclk(struct intel_atomic_state *state)
                 * Also serialize commits across all crtcs
                 * if the actual hw needs to be poked.
                 */
-               ret = intel_atomic_serialize_global_state(state);
+               ret = _intel_atomic_serialize_global_state(state);
                if (ret)
                        return ret;
        } else if (intel_cdclk_changed(&old_cdclk_state->logical,
                                       &new_cdclk_state->logical)) {
-               ret = intel_atomic_lock_global_state(state);
+               ret = _intel_atomic_lock_global_state(state);
                if (ret)
                        return ret;
        } else {

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index cced6b9b8ee2909b6c851872d28b098023a8f2aa..63a3e96cbaf5a9c7830f66a4b6cf49e4453cc366 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -14562,7 +14562,7 @@ static int intel_modeset_checks(struct intel_atomic_state *state)
        }
 
        if (state->active_pipe_changes) {
-               ret = intel_atomic_lock_global_state(state);
+               ret = _intel_atomic_lock_global_state(state);
                if (ret)
                        return ret;
        }
@@ -15842,6 +15842,8 @@ static int intel_atomic_commit(struct drm_device *dev,
        ret = drm_atomic_helper_setup_commit(&state->base, nonblock);
        if (!ret)
                ret = drm_atomic_helper_swap_state(&state->base, true);
+       if (!ret)
+               intel_atomic_swap_global_state(state);
 
        if (ret) {
                i915_sw_fence_commit(&state->commit_ready);
@@ -17759,6 +17761,7 @@ static void intel_mode_config_init(struct drm_i915_private *i915)
        struct drm_mode_config *mode_config = &i915->drm.mode_config;
 
        drm_mode_config_init(&i915->drm);
+       INIT_LIST_HEAD(&i915->global_obj_list);
 
        mode_config->min_width = 0;
        mode_config->min_height = 0;
@@ -17800,6 +17803,12 @@ static void intel_mode_config_init(struct drm_i915_private *i915)
        }
 }
 
+static void intel_mode_config_cleanup(struct drm_i915_private *i915)
+{
+       intel_atomic_global_obj_cleanup(i915);
+       drm_mode_config_cleanup(&i915->drm);
+}
+
 int intel_modeset_init(struct drm_i915_private *i915)
 {
        struct drm_device *dev = &i915->drm;
@@ -17839,7 +17848,7 @@ int intel_modeset_init(struct drm_i915_private *i915)
                for_each_pipe(i915, pipe) {
                        ret = intel_crtc_init(i915, pipe);
                        if (ret) {
-                               drm_mode_config_cleanup(dev);
+                               intel_mode_config_cleanup(i915);
                                return ret;
                        }
                }
@@ -18807,7 +18816,7 @@ void intel_modeset_driver_remove(struct drm_i915_private *i915)
 
        intel_hdcp_component_fini(i915);
 
-       drm_mode_config_cleanup(&i915->drm);
+       intel_mode_config_cleanup(i915);
 
        intel_overlay_cleanup(i915);
 

diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index aa2e212f5db2e8344a16ff85b282b02af2a420a2..efeda019ba79a8f38f8507f13fe65cfd232d42a2 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -47,6 +47,7 @@
 #include "intel_de.h"
 
 struct drm_printer;
+struct __intel_global_objs_state;
 
 /*
  * Display related stuff
@@ -462,6 +463,9 @@ struct intel_atomic_state {
 
        intel_wakeref_t wakeref;
 
+       struct __intel_global_objs_state *global_objs;
+       int num_global_objs;
+
        struct intel_cdclk_state cdclk_state;
 
        bool dpll_set, modeset;

diff --git a/drivers/gpu/drm/i915/display/intel_global_state.c b/drivers/gpu/drm/i915/display/intel_global_state.c
new file mode 100644 (file)
index 0000000..a0cc894
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_global_state.c
@@ -0,0 +1,223 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2020 Intel Corporation
+ */
+
+#include <linux/string.h>
+
+#include "i915_drv.h"
+#include "intel_atomic.h"
+#include "intel_display_types.h"
+#include "intel_global_state.h"
+
+void intel_atomic_global_obj_init(struct drm_i915_private *dev_priv,
+                                 struct intel_global_obj *obj,
+                                 struct intel_global_state *state,
+                                 const struct intel_global_state_funcs *funcs)
+{
+       memset(obj, 0, sizeof(*obj));
+
+       obj->state = state;
+       obj->funcs = funcs;
+       list_add_tail(&obj->head, &dev_priv->global_obj_list);
+}
+
+void intel_atomic_global_obj_cleanup(struct drm_i915_private *dev_priv)
+{
+       struct intel_global_obj *obj, *next;
+
+       list_for_each_entry_safe(obj, next, &dev_priv->global_obj_list, head) {
+               list_del(&obj->head);
+               obj->funcs->atomic_destroy_state(obj, obj->state);
+       }
+}
+
+static void assert_global_state_write_locked(struct drm_i915_private *dev_priv)
+{
+       struct intel_crtc *crtc;
+
+       for_each_intel_crtc(&dev_priv->drm, crtc)
+               drm_modeset_lock_assert_held(&crtc->base.mutex);
+}
+
+static bool modeset_lock_is_held(struct drm_modeset_acquire_ctx *ctx,
+                                struct drm_modeset_lock *lock)
+{
+       struct drm_modeset_lock *l;
+
+       list_for_each_entry(l, &ctx->locked, head) {
+               if (lock == l)
+                       return true;
+       }
+
+       return false;
+}
+
+static void assert_global_state_read_locked(struct intel_atomic_state *state)
+{
+       struct drm_modeset_acquire_ctx *ctx = state->base.acquire_ctx;
+       struct drm_i915_private *dev_priv = to_i915(state->base.dev);
+       struct intel_crtc *crtc;
+
+       for_each_intel_crtc(&dev_priv->drm, crtc) {
+               if (modeset_lock_is_held(ctx, &crtc->base.mutex))
+                       return;
+       }
+
+       WARN(1, "Global state not read locked\n");
+}
+
+struct intel_global_state *
+intel_atomic_get_global_obj_state(struct intel_atomic_state *state,
+                                 struct intel_global_obj *obj)
+{
+       int index, num_objs, i;
+       size_t size;
+       struct __intel_global_objs_state *arr;
+       struct intel_global_state *obj_state;
+
+       for (i = 0; i < state->num_global_objs; i++)
+               if (obj == state->global_objs[i].ptr)
+                       return state->global_objs[i].state;
+
+       assert_global_state_read_locked(state);
+
+       num_objs = state->num_global_objs + 1;
+       size = sizeof(*state->global_objs) * num_objs;
+       arr = krealloc(state->global_objs, size, GFP_KERNEL);
+       if (!arr)
+               return ERR_PTR(-ENOMEM);
+
+       state->global_objs = arr;
+       index = state->num_global_objs;
+       memset(&state->global_objs[index], 0, sizeof(*state->global_objs));
+
+       obj_state = obj->funcs->atomic_duplicate_state(obj);
+       if (!obj_state)
+               return ERR_PTR(-ENOMEM);
+
+       obj_state->changed = false;
+
+       state->global_objs[index].state = obj_state;
+       state->global_objs[index].old_state = obj->state;
+       state->global_objs[index].new_state = obj_state;
+       state->global_objs[index].ptr = obj;
+       obj_state->state = state;
+
+       state->num_global_objs = num_objs;
+
+       DRM_DEBUG_ATOMIC("Added new global object %p state %p to %p\n",
+                        obj, obj_state, state);
+
+       return obj_state;
+}
+
+struct intel_global_state *
+intel_atomic_get_old_global_obj_state(struct intel_atomic_state *state,
+                                     struct intel_global_obj *obj)
+{
+       int i;
+
+       for (i = 0; i < state->num_global_objs; i++)
+               if (obj == state->global_objs[i].ptr)
+                       return state->global_objs[i].old_state;
+
+       return NULL;
+}
+
+struct intel_global_state *
+intel_atomic_get_new_global_obj_state(struct intel_atomic_state *state,
+                                     struct intel_global_obj *obj)
+{
+       int i;
+
+       for (i = 0; i < state->num_global_objs; i++)
+               if (obj == state->global_objs[i].ptr)
+                       return state->global_objs[i].new_state;
+
+       return NULL;
+}
+
+void intel_atomic_swap_global_state(struct intel_atomic_state *state)
+{
+       struct drm_i915_private *dev_priv = to_i915(state->base.dev);
+       struct intel_global_state *old_obj_state, *new_obj_state;
+       struct intel_global_obj *obj;
+       int i;
+
+       for_each_oldnew_global_obj_in_state(state, obj, old_obj_state,
+                                           new_obj_state, i) {
+               WARN_ON(obj->state != old_obj_state);
+
+               /*
+                * If the new state wasn't modified (and properly
+                * locked for write access) we throw it away.
+                */
+               if (!new_obj_state->changed)
+                       continue;
+
+               assert_global_state_write_locked(dev_priv);
+
+               old_obj_state->state = state;
+               new_obj_state->state = NULL;
+
+               state->global_objs[i].state = old_obj_state;
+               obj->state = new_obj_state;
+       }
+}
+
+void intel_atomic_clear_global_state(struct intel_atomic_state *state)
+{
+       int i;
+
+       for (i = 0; i < state->num_global_objs; i++) {
+               struct intel_global_obj *obj = state->global_objs[i].ptr;
+
+               obj->funcs->atomic_destroy_state(obj,
+                                                state->global_objs[i].state);
+               state->global_objs[i].ptr = NULL;
+               state->global_objs[i].state = NULL;
+               state->global_objs[i].old_state = NULL;
+               state->global_objs[i].new_state = NULL;
+       }
+       state->num_global_objs = 0;
+}
+
+int intel_atomic_lock_global_state(struct intel_global_state *obj_state)
+{
+       struct intel_atomic_state *state = obj_state->state;
+       struct drm_i915_private *dev_priv = to_i915(state->base.dev);
+       struct intel_crtc *crtc;
+
+       for_each_intel_crtc(&dev_priv->drm, crtc) {
+               int ret;
+
+               ret = drm_modeset_lock(&crtc->base.mutex,
+                                      state->base.acquire_ctx);
+               if (ret)
+                       return ret;
+       }
+
+       obj_state->changed = true;
+
+       return 0;
+}
+
+int intel_atomic_serialize_global_state(struct intel_global_state *obj_state)
+{
+       struct intel_atomic_state *state = obj_state->state;
+       struct drm_i915_private *dev_priv = to_i915(state->base.dev);
+       struct intel_crtc *crtc;
+
+       for_each_intel_crtc(&dev_priv->drm, crtc) {
+               struct intel_crtc_state *crtc_state;
+
+               crtc_state = intel_atomic_get_crtc_state(&state->base, crtc);
+               if (IS_ERR(crtc_state))
+                       return PTR_ERR(crtc_state);
+       }
+
+       obj_state->changed = true;
+
+       return 0;
+}

diff --git a/drivers/gpu/drm/i915/display/intel_global_state.h b/drivers/gpu/drm/i915/display/intel_global_state.h
new file mode 100644 (file)
index 0000000..e6163a4
--- /dev/null
+++ b/drivers/gpu/drm/i915/display/intel_global_state.h
@@ -0,0 +1,87 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2020 Intel Corporation
+ */
+
+#ifndef __INTEL_GLOBAL_STATE_H__
+#define __INTEL_GLOBAL_STATE_H__
+
+#include <linux/list.h>
+
+struct drm_i915_private;
+struct intel_atomic_state;
+struct intel_global_obj;
+struct intel_global_state;
+
+struct intel_global_state_funcs {
+       struct intel_global_state *(*atomic_duplicate_state)(struct intel_global_obj *obj);
+       void (*atomic_destroy_state)(struct intel_global_obj *obj,
+                                    struct intel_global_state *state);
+};
+
+struct intel_global_obj {
+       struct list_head head;
+       struct intel_global_state *state;
+       const struct intel_global_state_funcs *funcs;
+};
+
+#define intel_for_each_global_obj(obj, dev_priv) \
+       list_for_each_entry(obj, &(dev_priv)->global_obj_list, head)
+
+#define for_each_new_global_obj_in_state(__state, obj, new_obj_state, __i) \
+       for ((__i) = 0; \
+            (__i) < (__state)->num_global_objs && \
+                    ((obj) = (__state)->global_objs[__i].ptr, \
+                     (new_obj_state) = (__state)->global_objs[__i].new_state, 1); \
+            (__i)++) \
+               for_each_if(obj)
+
+#define for_each_old_global_obj_in_state(__state, obj, new_obj_state, __i) \
+       for ((__i) = 0; \
+            (__i) < (__state)->num_global_objs && \
+                    ((obj) = (__state)->global_objs[__i].ptr, \
+                     (new_obj_state) = (__state)->global_objs[__i].old_state, 1); \
+            (__i)++) \
+               for_each_if(obj)
+
+#define for_each_oldnew_global_obj_in_state(__state, obj, old_obj_state, new_obj_state, __i) \
+       for ((__i) = 0; \
+            (__i) < (__state)->num_global_objs && \
+                    ((obj) = (__state)->global_objs[__i].ptr, \
+                     (old_obj_state) = (__state)->global_objs[__i].old_state, \
+                     (new_obj_state) = (__state)->global_objs[__i].new_state, 1); \
+            (__i)++) \
+               for_each_if(obj)
+
+struct intel_global_state {
+       struct intel_atomic_state *state;
+       bool changed;
+};
+
+struct __intel_global_objs_state {
+       struct intel_global_obj *ptr;
+       struct intel_global_state *state, *old_state, *new_state;
+};
+
+void intel_atomic_global_obj_init(struct drm_i915_private *dev_priv,
+                                 struct intel_global_obj *obj,
+                                 struct intel_global_state *state,
+                                 const struct intel_global_state_funcs *funcs);
+void intel_atomic_global_obj_cleanup(struct drm_i915_private *dev_priv);
+
+struct intel_global_state *
+intel_atomic_get_global_obj_state(struct intel_atomic_state *state,
+                                 struct intel_global_obj *obj);
+struct intel_global_state *
+intel_atomic_get_old_global_obj_state(struct intel_atomic_state *state,
+                                     struct intel_global_obj *obj);
+struct intel_global_state *
+intel_atomic_get_new_global_obj_state(struct intel_atomic_state *state,
+                                     struct intel_global_obj *obj);
+
+void intel_atomic_swap_global_state(struct intel_atomic_state *state);
+void intel_atomic_clear_global_state(struct intel_atomic_state *state);
+int intel_atomic_lock_global_state(struct intel_global_state *obj_state);
+int intel_atomic_serialize_global_state(struct intel_global_state *obj_state);
+
+#endif

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1ab8238e09fe2d5dc70cbef9ac2cc0e56ca2f420..3ed48371f3dac3c3847997f9ee6239ae3fc0c918 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -71,6 +71,7 @@
 #include "display/intel_dpll_mgr.h"
 #include "display/intel_dsb.h"
 #include "display/intel_frontbuffer.h"
+#include "display/intel_global_state.h"
 #include "display/intel_gmbus.h"
 #include "display/intel_opregion.h"
 
@@ -1098,6 +1099,8 @@ struct drm_i915_private {
         */
        struct mutex dpll_lock;
 
+       struct list_head global_obj_list;
+
        /*
         * For reading active_pipes, cdclk_state holding any crtc
         * lock is sufficient, for writing must hold all of them.