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Commit 132458d8 authored by Raviteja Tamatam's avatar Raviteja Tamatam
Browse files

drm/msm/sde: fix race condition in vblank control interrupts 



In Dual display concurrencies there are certain cases where
irq_idx and vblank_refcount state mismatch can occur.
To avoid it, during setup of irq_hw_idx, reset the vblank_refcount
and unregister read ptr irq if not yet done by then.
Also, if register IRQ fails, correct vblank_refcount so
that IRQ registration can be tried again.

Change-Id: I06bcbf71c6a43bd161ff61093d9f6063a292d6bc
Signed-off-by: default avatarRaviteja Tamatam <travitej@codeaurora.org>
parent 1d8b3d68

drivers/gpu/drm/msm/sde/sde_encoder_phys_cmd.c

+27 −2
Original line number Diff line number Diff line
@@ -375,6 +375,7 @@ static void _sde_encoder_phys_cmd_setup_irq_hw_idx( 
		struct sde_encoder_phys *phys_enc)

{

	struct sde_encoder_irq *irq;

	int ret = 0;



	if (!phys_enc || !phys_enc->hw_pp || !phys_enc->hw_ctl) {

		SDE_ERROR("invalid args %d %d\n", !phys_enc,
@@ -387,6 +388,22 @@ static void _sde_encoder_phys_cmd_setup_irq_hw_idx( 
		return;

	}



	mutex_lock(phys_enc->vblank_ctl_lock);



	if (atomic_read(&phys_enc->vblank_refcount)) {

		SDE_ERROR(

		"vblank_refcount mismatch detected, try to reset %d\n",

				atomic_read(&phys_enc->vblank_refcount));

		ret = sde_encoder_helper_unregister_irq(phys_enc,

				INTR_IDX_RDPTR);

		if (ret)

			SDE_ERROR(

			"control vblank irq registration error %d\n",

				ret);

	}



	atomic_set(&phys_enc->vblank_refcount, 0);



	irq = &phys_enc->irq[INTR_IDX_CTL_START];

	irq->hw_idx = phys_enc->hw_ctl->idx;

	irq->irq_idx = -EINVAL;
@@ -412,6 +429,8 @@ static void _sde_encoder_phys_cmd_setup_irq_hw_idx( 
		irq->hw_idx = phys_enc->hw_intf->idx;

	else

		irq->hw_idx = phys_enc->hw_pp->idx;



	mutex_unlock(phys_enc->vblank_ctl_lock);

}



static void sde_encoder_phys_cmd_cont_splash_mode_set(
@@ -825,11 +844,17 @@ static int sde_encoder_phys_cmd_control_vblank_irq( 
	SDE_EVT32(DRMID(phys_enc->parent), phys_enc->hw_pp->idx - PINGPONG_0,

			enable, refcount);



	if (enable && atomic_inc_return(&phys_enc->vblank_refcount) == 1)

	if (enable && atomic_inc_return(&phys_enc->vblank_refcount) == 1) {

		ret = sde_encoder_helper_register_irq(phys_enc, INTR_IDX_RDPTR);

	else if (!enable && atomic_dec_return(&phys_enc->vblank_refcount) == 0)

		if (ret)

			atomic_dec_return(&phys_enc->vblank_refcount);

	} else if (!enable &&

			atomic_dec_return(&phys_enc->vblank_refcount) == 0) {

		ret = sde_encoder_helper_unregister_irq(phys_enc,

				INTR_IDX_RDPTR);

		if (ret)

			atomic_inc_return(&phys_enc->vblank_refcount);

	}



end:

	if (ret) {