[PATCH] drm/amdgpu: Fix dead lock issue for vblank

[Deng, Emily]

[AMD Official Use Only - Internal Distribution Only]

Hi Hawking,
    You are right, my base is not the tip. I have updated now. Please help to review again.

Best wishes
Emily Deng



>-----Original Message-----
>From: Emily.Deng <Emily.Deng at amd.com>
>Sent: Friday, September 18, 2020 6:13 PM
>To: amd-gfx at lists.freedesktop.org
>Cc: Deng, Emily <Emily.Deng at amd.com>
>Subject: [PATCH] drm/amdgpu: Fix dead lock issue for vblank
>
>Always start vblank timer, but only calls vblank function when vblank is enabled.
>
>This is used to fix the dead lock issue.
>When drm_crtc_vblank_off want to disable vblank, it first get event_lock, and
>then call hrtimer_cancel, but hrtimer_cancel want to wait timer handler
>function finished.
>Timer handler also want to aquire event_lock in drm_handle_vblank.
>
>Signed-off-by: Emily.Deng <Emily.Deng at amd.com>
>Change-Id: I7d3cfb1202cd030fdcdec3e7483fcc4c9fa8db70
>---
> drivers/gpu/drm/amd/amdgpu/dce_virtual.c | 35 ++++++++++++------------
> 1 file changed, 17 insertions(+), 18 deletions(-)
>
>diff --git a/drivers/gpu/drm/amd/amdgpu/dce_virtual.c
>b/drivers/gpu/drm/amd/amdgpu/dce_virtual.c
>index cc93577dee03..469c05fd43d5 100644
>--- a/drivers/gpu/drm/amd/amdgpu/dce_virtual.c
>+++ b/drivers/gpu/drm/amd/amdgpu/dce_virtual.c
>@@ -47,6 +47,9 @@ static void dce_virtual_set_display_funcs(struct
>amdgpu_device *adev);  static void dce_virtual_set_irq_funcs(struct
>amdgpu_device *adev);  static int dce_virtual_connector_encoder_init(struct
>amdgpu_device *adev,
>       int index);
>+static int dce_virtual_pageflip(struct amdgpu_device *adev,
>+unsigned crtc_id);
>+static enum hrtimer_restart dce_virtual_vblank_timer_handle(struct
>+hrtimer *vblank_timer);
> static void dce_virtual_set_crtc_vblank_interrupt_state(struct amdgpu_device
>*adev,
> int crtc,
> enum
>amdgpu_interrupt_state state); @@ -247,6 +250,11 @@ static int
>dce_virtual_crtc_init(struct amdgpu_device *adev, int index)
> amdgpu_crtc->vsync_timer_enabled = AMDGPU_IRQ_STATE_DISABLE;
> drm_crtc_helper_add(&amdgpu_crtc->base,
>&dce_virtual_crtc_helper_funcs);
>
>+hrtimer_init(&amdgpu_crtc->vblank_timer, CLOCK_MONOTONIC,
>HRTIMER_MODE_REL);
>+hrtimer_set_expires(&amdgpu_crtc->vblank_timer,
>DCE_VIRTUAL_VBLANK_PERIOD);
>+amdgpu_crtc->vblank_timer.function =
>dce_virtual_vblank_timer_handle;
>+hrtimer_start(&amdgpu_crtc->vblank_timer,
>+      DCE_VIRTUAL_VBLANK_PERIOD, HRTIMER_MODE_REL);
> return 0;
> }
>
>@@ -476,7 +484,7 @@ static int dce_virtual_hw_fini(void *handle)
>
> for (i = 0; i<adev->mode_info.num_crtc; i++)
> if (adev->mode_info.crtcs[i])
>-dce_virtual_set_crtc_vblank_interrupt_state(adev, i,
>AMDGPU_IRQ_STATE_DISABLE);
>+hrtimer_cancel(&adev->mode_info.crtcs[i]-
>>vblank_timer);
>
> return 0;
> }
>@@ -698,9 +706,15 @@ static enum hrtimer_restart
>dce_virtual_vblank_timer_handle(struct hrtimer *vbla
>        struct amdgpu_crtc,
>vblank_timer);
> struct drm_device *ddev = amdgpu_crtc->base.dev;
> struct amdgpu_device *adev = drm_to_adev(ddev);
>+struct amdgpu_irq_src *source = adev-
>>irq.client[AMDGPU_IRQ_CLIENTID_LEGACY].sources
>+[VISLANDS30_IV_SRCID_SMU_DISP_TIMER2_TRIGGER];
>+int irq_type = amdgpu_display_crtc_idx_to_irq_type(adev,
>+amdgpu_crtc->crtc_id);
>
>-drm_handle_vblank(ddev, amdgpu_crtc->crtc_id);
>-dce_virtual_pageflip(adev, amdgpu_crtc->crtc_id);
>+if (amdgpu_irq_enabled(adev, source, irq_type)) {
>+drm_handle_vblank(ddev, amdgpu_crtc->crtc_id);
>+dce_virtual_pageflip(adev, amdgpu_crtc->crtc_id);
>+}
> hrtimer_start(vblank_timer, DCE_VIRTUAL_VBLANK_PERIOD,
>       HRTIMER_MODE_REL);
>
>@@ -716,21 +730,6 @@ static void
>dce_virtual_set_crtc_vblank_interrupt_state(struct amdgpu_device *ad
> return;
> }
>
>-if (state && !adev->mode_info.crtcs[crtc]->vsync_timer_enabled) {
>-DRM_DEBUG("Enable software vsync timer\n");
>-hrtimer_init(&adev->mode_info.crtcs[crtc]->vblank_timer,
>-     CLOCK_MONOTONIC, HRTIMER_MODE_REL);
>-hrtimer_set_expires(&adev->mode_info.crtcs[crtc]-
>>vblank_timer,
>-    DCE_VIRTUAL_VBLANK_PERIOD);
>-adev->mode_info.crtcs[crtc]->vblank_timer.function =
>-dce_virtual_vblank_timer_handle;
>-hrtimer_start(&adev->mode_info.crtcs[crtc]->vblank_timer,
>-      DCE_VIRTUAL_VBLANK_PERIOD,
>HRTIMER_MODE_REL);
>-} else if (!state && adev->mode_info.crtcs[crtc]->vsync_timer_enabled)
>{
>-DRM_DEBUG("Disable software vsync timer\n");
>-hrtimer_cancel(&adev->mode_info.crtcs[crtc]->vblank_timer);
>-}
>-
> adev->mode_info.crtcs[crtc]->vsync_timer_enabled = state;
> DRM_DEBUG("[FM]set crtc %d vblank interrupt state %d\n", crtc,
>state);  }
>--
>2.25.1