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drm/rockchip: vop: fix display flash when switch to iommu mapping

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Do iommu mapping with looping vop vblank register have a problem, when
iommu attach take too long time or vblank time is too short, the display
would flash.

This patch use another method to fix this problem:
  Use standby and dsp_hold interrupt to enter vblank time, when iommu
  mapping is finish, exit vop standby, then vop would start scanout
  immediately,
      vop enter standby    -> |
      dsp_hold irq         -> |--------- vblank start
      do iommu mapping     -> | vblank time
      exit standby         -> |--------- vblank end

We try add 20ms delay to iommu attach, display also looks good, that
means this method have higher compatibility.

Change-Id: I59d57c9085631d0c42174ea18890c80e26b42d22
Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
This commit is contained in:
Mark Yao
2016-11-28 08:46:29 +08:00
committed by Huang, Tao
parent 078f5873cf
commit 939aa1c509
1 changed files with 13 additions and 1 deletions
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14
drivers/gpu/drm/rockchip/rockchip_drm_vop.c
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@@ -1536,13 +1536,25 @@ static void vop_crtc_atomic_flush(struct drm_crtc *crtc,
if (!vop->is_iommu_enabled && vop->is_iommu_needed) {
int ret;
if (!vop_is_allwin_disabled(vop)) {
reinit_completion(&vop->dsp_hold_completion);
vop_dsp_hold_valid_irq_enable(vop);
vop_cfg_update(crtc, old_crtc_state);
while(!vop_is_cfg_done_complete(vop));
spin_lock(&vop->reg_lock);
VOP_CTRL_SET(vop, standby, 1);
spin_unlock(&vop->reg_lock);
wait_for_completion(&vop->dsp_hold_completion);
vop_dsp_hold_valid_irq_disable(vop);
}
ret = rockchip_drm_dma_attach_device(vop->drm_dev, vop->dev);
if (ret) {
dev_err(vop->dev, "failed to attach dma mapping, %d\n", ret);
}
VOP_CTRL_SET(vop, standby, 0);
vop->is_iommu_enabled = true;
}