Le 05/06/2025 à 17:24, Thomas Zimmermann a écrit :
Replace vkms' vblank timer with the DRM implementation. The DRM
code is mostly identical.

Signed-off-by: Thomas Zimmermann <tzimmerm...@suse.de>

Reviewed-by: Louis Chauvet <louis.chau...@bootlin.com>
Tested-by: Louis Chauvet <louis.chauvet@bootlin>

---
  drivers/gpu/drm/vkms/vkms_crtc.c | 49 +++++++-------------------------
  drivers/gpu/drm/vkms/vkms_drv.h  |  6 ++--
  2 files changed, 15 insertions(+), 40 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c
index 8c9898b9055d..5b7829e8c900 100644
--- a/drivers/gpu/drm/vkms/vkms_crtc.c
+++ b/drivers/gpu/drm/vkms/vkms_crtc.c
@@ -10,22 +10,14 @@
#include "vkms_drv.h" -static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
+static bool vkms_crtc_handle_vblank(struct drm_crtc *crtc)
  {
-       struct vkms_output *output = container_of(timer, struct vkms_output,
-                                                 vblank_hrtimer);
-       struct drm_crtc *crtc = &output->crtc;
+       struct vkms_output *output = drm_crtc_to_vkms_output(crtc);
        struct vkms_crtc_state *state;
-       u64 ret_overrun;
        bool ret, fence_cookie;
fence_cookie = dma_fence_begin_signalling(); - ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer,
-                                         output->period_ns);
-       if (ret_overrun != 1)
-               pr_warn("%s: vblank timer overrun\n", __func__);
-
        spin_lock(&output->lock);
        ret = drm_crtc_handle_vblank(crtc);
        if (!ret)
@@ -57,18 +49,14 @@ static enum hrtimer_restart vkms_vblank_simulate(struct 
hrtimer *timer)
dma_fence_end_signalling(fence_cookie); - return HRTIMER_RESTART;
+       return true;
  }
static int vkms_enable_vblank(struct drm_crtc *crtc)
  {
-       struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc);
        struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
- hrtimer_setup(&out->vblank_hrtimer, &vkms_vblank_simulate, CLOCK_MONOTONIC,
-                     HRTIMER_MODE_REL);
-       out->period_ns = ktime_set(0, vblank->framedur_ns);
-       hrtimer_start(&out->vblank_hrtimer, out->period_ns, HRTIMER_MODE_REL);
+       drm_vblank_timer_start(&out->vtimer);
return 0;
  }
@@ -77,7 +65,7 @@ static void vkms_disable_vblank(struct drm_crtc *crtc)
  {
        struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
- hrtimer_cancel(&out->vblank_hrtimer);
+       drm_vblank_timer_cancel(&out->vtimer);
  }
static bool vkms_get_vblank_timestamp(struct drm_crtc *crtc,
@@ -85,28 +73,9 @@ static bool vkms_get_vblank_timestamp(struct drm_crtc *crtc,
                                      bool in_vblank_irq)
  {
        struct vkms_output *output = drm_crtc_to_vkms_output(crtc);
-       struct drm_vblank_crtc *vblank = drm_crtc_vblank_crtc(crtc);
-
-       if (!READ_ONCE(vblank->enabled)) {
-               *vblank_time = ktime_get();
-               return true;
-       }
-
-       *vblank_time = READ_ONCE(output->vblank_hrtimer.node.expires);
- if (WARN_ON(*vblank_time == vblank->time))
-               return true;
-
-       /*
-        * To prevent races we roll the hrtimer forward before we do any
-        * interrupt processing - this is how real hw works (the interrupt is
-        * only generated after all the vblank registers are updated) and what
-        * the vblank core expects. Therefore we need to always correct the
-        * timestampe by one frame.
-        */
-       *vblank_time -= output->period_ns;
-
-       return true;
+       return drm_vblank_timer_get_vblank_timestamp(&output->vtimer, max_error,
+                                                    vblank_time, 
in_vblank_irq);
  }
static struct drm_crtc_state *
@@ -274,6 +243,7 @@ struct vkms_output *vkms_crtc_init(struct drm_device *dev, 
struct drm_plane *pri
  {
        struct vkms_output *vkms_out;
        struct drm_crtc *crtc;
+       struct drm_vblank_timer *vtimer;
        int ret;
vkms_out = drmm_crtc_alloc_with_planes(dev, struct vkms_output, crtc,
@@ -285,6 +255,7 @@ struct vkms_output *vkms_crtc_init(struct drm_device *dev, 
struct drm_plane *pri
        }
crtc = &vkms_out->crtc;
+       vtimer = &vkms_out->vtimer;
drm_crtc_helper_add(crtc, &vkms_crtc_helper_funcs); @@ -305,5 +276,7 @@ struct vkms_output *vkms_crtc_init(struct drm_device *dev, struct drm_plane *pri
        if (!vkms_out->composer_workq)
                return ERR_PTR(-ENOMEM);
+ drmm_vblank_timer_init(vtimer, crtc, vkms_crtc_handle_vblank);
+
        return vkms_out;
  }
diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
index a74a7fc3a056..126016898285 100644
--- a/drivers/gpu/drm/vkms/vkms_drv.h
+++ b/drivers/gpu/drm/vkms/vkms_drv.h
@@ -10,6 +10,7 @@
  #include <drm/drm_gem.h>
  #include <drm/drm_gem_atomic_helper.h>
  #include <drm/drm_encoder.h>
+#include <drm/drm_vblank_timer.h>
  #include <drm/drm_writeback.h>
#define DEFAULT_DEVICE_NAME "vkms"
@@ -180,8 +181,9 @@ struct vkms_output {
        struct drm_crtc crtc;
        struct drm_writeback_connector wb_connector;
        struct drm_encoder wb_encoder;
-       struct hrtimer vblank_hrtimer;
-       ktime_t period_ns;
+       struct drm_vblank_timer vtimer;
+       struct drm_pending_vblank_event *event;
+       /* ordered wq for composer_work */
        struct workqueue_struct *composer_workq;
        spinlock_t lock;

--
Louis Chauvet, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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