drm/nouveau/clk: schedule pstate changes through a workqueue

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/core/include/subdev/clock.h b/drivers/gpu/drm/nouveau/core/include/subdev/clock.h
index c01e29c..3168e1a 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/include/subdev/clock.h
+++ b/drivers/gpu/drm/nouveau/core/include/subdev/clock.h
@@ -71,6 +71,10 @@ struct nouveau_clock {
        struct list_head states;
        int state_nr;
 
+       struct work_struct work;
+       wait_queue_head_t wait;
+       atomic_t waiting;
+
        int pstate; /* current */
        int ustate; /* user-requested (-1 disabled, -2 perfmon) */
        int astate; /* perfmon adjustment (base) */

diff --git a/drivers/gpu/drm/nouveau/core/subdev/clock/base.c b/drivers/gpu/drm/nouveau/core/subdev/clock/base.c
index 22351f5..7796637 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/subdev/clock/base.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/clock/base.c
@@ -194,10 +194,14 @@ nouveau_pstate_prog(struct nouveau_clock *clk, int pstatei)
        return nouveau_cstate_prog(clk, pstate, 0);
 }
 
-static int
-nouveau_pstate_calc(struct nouveau_clock *clk)
+static void
+nouveau_pstate_work(struct work_struct *work)
 {
-       int pstate, ret = 0;
+       struct nouveau_clock *clk = container_of(work, typeof(*clk), work);
+       int pstate;
+
+       if (!atomic_xchg(&clk->waiting, 0))
+               return;
 
        nv_trace(clk, "P %d U %d A %d T %d D %d\n", clk->pstate,
                 clk->ustate, clk->astate, clk->tstate, clk->dstate);
@@ -211,9 +215,25 @@ nouveau_pstate_calc(struct nouveau_clock *clk)
        }
 
        nv_trace(clk, "-> %d\n", pstate);
-       if (pstate != clk->pstate)
-               ret = nouveau_pstate_prog(clk, pstate);
-       return ret;
+       if (pstate != clk->pstate) {
+               int ret = nouveau_pstate_prog(clk, pstate);
+               if (ret) {
+                       nv_error(clk, "error setting pstate %d: %d\n",
+                                pstate, ret);
+               }
+       }
+
+       wake_up_all(&clk->wait);
+}
+
+static int
+nouveau_pstate_calc(struct nouveau_clock *clk, bool wait)
+{
+       atomic_set(&clk->waiting, 1);
+       schedule_work(&clk->work);
+       if (wait)
+               wait_event(clk->wait, !atomic_read(&clk->waiting));
+       return 0;
 }
 
 static void
@@ -371,7 +391,7 @@ nouveau_clock_ustate(struct nouveau_clock *clk, int req)
        int ret = nouveau_clock_ustate_update(clk, req);
        if (ret)
                return ret;
-       return nouveau_pstate_calc(clk);
+       return nouveau_pstate_calc(clk, true);
 }
 
 int
@@ -381,7 +401,7 @@ nouveau_clock_astate(struct nouveau_clock *clk, int req, int rel)
        if ( rel) clk->astate += rel;
        clk->astate = min(clk->astate, clk->state_nr - 1);
        clk->astate = max(clk->astate, 0);
-       return nouveau_pstate_calc(clk);
+       return nouveau_pstate_calc(clk, true);
 }
 
 int
@@ -391,7 +411,7 @@ nouveau_clock_tstate(struct nouveau_clock *clk, int req, int rel)
        if ( rel) clk->tstate += rel;
        clk->tstate = min(clk->tstate, 0);
        clk->tstate = max(clk->tstate, -(clk->state_nr - 1));
-       return nouveau_pstate_calc(clk);
+       return nouveau_pstate_calc(clk, true);
 }
 
 int
@@ -401,7 +421,7 @@ nouveau_clock_dstate(struct nouveau_clock *clk, int req, int rel)
        if ( rel) clk->dstate += rel;
        clk->dstate = min(clk->dstate, clk->state_nr - 1);
        clk->dstate = max(clk->dstate, 0);
-       return nouveau_pstate_calc(clk);
+       return nouveau_pstate_calc(clk, true);
 }
 
 /******************************************************************************
@@ -434,7 +454,7 @@ _nouveau_clock_init(struct nouveau_object *object)
        clk->tstate = 0;
        clk->dstate = 0;
        clk->pstate = -1;
-       nouveau_pstate_calc(clk);
+       nouveau_pstate_calc(clk, true);
        return 0;
 }
 
@@ -474,6 +494,10 @@ nouveau_clock_create_(struct nouveau_object *parent,
        clk->domains = clocks;
        clk->ustate = -1;
 
+       INIT_WORK(&clk->work, nouveau_pstate_work);
+       init_waitqueue_head(&clk->wait);
+       atomic_set(&clk->waiting, 0);
+
        idx = 0;
        do {
                ret = nouveau_pstate_new(clk, idx++);