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drm/i915: Manage PIPESTAT to control vblank interrupts instead of IMR.
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The pipestat fields affect reporting of all vblank-related interrupts, so we
have to reset them during the irq_handler, and while enabling vblank
interrupts.  Otherwise, if a pipe status field had been set to non-zero
before enabling reporting, we would never see an interrupt again.

This patch adds i915_enable_pipestat and i915_disable_pipestat to abstract
out the steps needed to change the reported interrupts.

Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
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Keith Packard authored and Dave Airlie committed Nov 24, 2008
1 parent ed31348 commit 7c46358
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Showing 3 changed files with 115 additions and 122 deletions.
8 changes: 8 additions & 0 deletions drivers/gpu/drm/i915/i915_drv.h
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Original file line number Diff line number Diff line change
Expand Up @@ -132,6 +132,7 @@ typedef struct drm_i915_private {
int user_irq_refcount;
/** Cached value of IMR to avoid reads in updating the bitfield */
u32 irq_mask_reg;
u32 pipestat[2];

int tex_lru_log_granularity;
int allow_batchbuffer;
Expand Down Expand Up @@ -446,6 +447,13 @@ extern int i915_vblank_swap(struct drm_device *dev, void *data,
struct drm_file *file_priv);
extern void i915_enable_irq(drm_i915_private_t *dev_priv, u32 mask);

void
i915_enable_pipestat(drm_i915_private_t *dev_priv, int pipe, u32 mask);

void
i915_disable_pipestat(drm_i915_private_t *dev_priv, int pipe, u32 mask);


/* i915_mem.c */
extern int i915_mem_alloc(struct drm_device *dev, void *data,
struct drm_file *file_priv);
Expand Down
211 changes: 99 additions & 112 deletions drivers/gpu/drm/i915/i915_irq.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -33,11 +33,23 @@

#define MAX_NOPID ((u32)~0)

/** These are the interrupts used by the driver */
#define I915_INTERRUPT_ENABLE_MASK (I915_USER_INTERRUPT | \
I915_ASLE_INTERRUPT | \
I915_DISPLAY_PIPE_A_EVENT_INTERRUPT | \
I915_DISPLAY_PIPE_B_EVENT_INTERRUPT)
/**
* Interrupts that are always left unmasked.
*
* Since pipe events are edge-triggered from the PIPESTAT register to IIR,
* we leave them always unmasked in IMR and then control enabling them through
* PIPESTAT alone.
*/
#define I915_INTERRUPT_ENABLE_FIX (I915_ASLE_INTERRUPT | \
I915_DISPLAY_PIPE_A_EVENT_INTERRUPT | \
I915_DISPLAY_PIPE_B_EVENT_INTERRUPT)

/** Interrupts that we mask and unmask at runtime. */
#define I915_INTERRUPT_ENABLE_VAR (I915_USER_INTERRUPT)

/** These are all of the interrupts used by the driver */
#define I915_INTERRUPT_ENABLE_MASK (I915_INTERRUPT_ENABLE_FIX | \
I915_INTERRUPT_ENABLE_VAR)

void
i915_enable_irq(drm_i915_private_t *dev_priv, u32 mask)
Expand All @@ -59,6 +71,41 @@ i915_disable_irq(drm_i915_private_t *dev_priv, u32 mask)
}
}

static inline u32
i915_pipestat(int pipe)
{
if (pipe == 0)
return PIPEASTAT;
if (pipe == 1)
return PIPEBSTAT;
BUG_ON(1);
}

void
i915_enable_pipestat(drm_i915_private_t *dev_priv, int pipe, u32 mask)
{
if ((dev_priv->pipestat[pipe] & mask) != mask) {
u32 reg = i915_pipestat(pipe);

dev_priv->pipestat[pipe] |= mask;
/* Enable the interrupt, clear any pending status */
I915_WRITE(reg, dev_priv->pipestat[pipe] | (mask >> 16));
(void) I915_READ(reg);
}
}

void
i915_disable_pipestat(drm_i915_private_t *dev_priv, int pipe, u32 mask)
{
if ((dev_priv->pipestat[pipe] & mask) != 0) {
u32 reg = i915_pipestat(pipe);

dev_priv->pipestat[pipe] &= ~mask;
I915_WRITE(reg, dev_priv->pipestat[pipe]);
(void) I915_READ(reg);
}
}

/**
* i915_pipe_enabled - check if a pipe is enabled
* @dev: DRM device
Expand Down Expand Up @@ -122,9 +169,11 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
struct drm_device *dev = (struct drm_device *) arg;
drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
u32 iir;
u32 pipea_stats, pipeb_stats;
u32 pipea_stats = 0, pipeb_stats = 0;
int vblank = 0;
unsigned long irqflags;

spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
atomic_inc(&dev_priv->irq_received);

if (dev->pdev->msi_enabled)
Expand All @@ -136,44 +185,20 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
I915_WRITE(IMR, dev_priv->irq_mask_reg);
(void) I915_READ(IMR);
}
spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
return IRQ_NONE;
}

/*
* Clear the PIPE(A|B)STAT regs before the IIR otherwise
* we may get extra interrupts.
* Clear the PIPE(A|B)STAT regs before the IIR
*/
if (iir & I915_DISPLAY_PIPE_A_EVENT_INTERRUPT) {
pipea_stats = I915_READ(PIPEASTAT);
if (!(dev_priv->vblank_pipe & DRM_I915_VBLANK_PIPE_A))
pipea_stats &= ~(PIPE_START_VBLANK_INTERRUPT_ENABLE |
PIPE_VBLANK_INTERRUPT_ENABLE);
else if (pipea_stats & (PIPE_START_VBLANK_INTERRUPT_STATUS|
PIPE_VBLANK_INTERRUPT_STATUS)) {
vblank++;
drm_handle_vblank(dev, 0);
}

I915_WRITE(PIPEASTAT, pipea_stats);
}

if (iir & I915_DISPLAY_PIPE_B_EVENT_INTERRUPT) {
pipeb_stats = I915_READ(PIPEBSTAT);
/* Ack the event */
I915_WRITE(PIPEBSTAT, pipeb_stats);

/* The vblank interrupt gets enabled even if we didn't ask for
it, so make sure it's shut down again */
if (!(dev_priv->vblank_pipe & DRM_I915_VBLANK_PIPE_B))
pipeb_stats &= ~(PIPE_START_VBLANK_INTERRUPT_ENABLE |
PIPE_VBLANK_INTERRUPT_ENABLE);
else if (pipeb_stats & (PIPE_START_VBLANK_INTERRUPT_STATUS|
PIPE_VBLANK_INTERRUPT_STATUS)) {
vblank++;
drm_handle_vblank(dev, 1);
}

if (pipeb_stats & I915_LEGACY_BLC_EVENT_STATUS)
opregion_asle_intr(dev);
I915_WRITE(PIPEBSTAT, pipeb_stats);
}

Expand All @@ -182,6 +207,8 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
I915_WRITE(IMR, dev_priv->irq_mask_reg);
(void) I915_READ(IIR); /* Flush posted writes */

spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);

if (dev_priv->sarea_priv)
dev_priv->sarea_priv->last_dispatch =
READ_BREADCRUMB(dev_priv);
Expand All @@ -191,7 +218,18 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
DRM_WAKEUP(&dev_priv->irq_queue);
}

if (iir & I915_ASLE_INTERRUPT)
if (pipea_stats & I915_VBLANK_INTERRUPT_STATUS) {
vblank++;
drm_handle_vblank(dev, 0);
}

if (pipeb_stats & I915_VBLANK_INTERRUPT_STATUS) {
vblank++;
drm_handle_vblank(dev, 1);
}

if ((pipeb_stats & I915_LEGACY_BLC_EVENT_STATUS) ||
(iir & I915_ASLE_INTERRUPT))
opregion_asle_intr(dev);

return IRQ_HANDLED;
Expand Down Expand Up @@ -330,48 +368,16 @@ int i915_irq_wait(struct drm_device *dev, void *data,
int i915_enable_vblank(struct drm_device *dev, int pipe)
{
drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
u32 pipestat_reg = 0;
u32 pipestat;
u32 interrupt = 0;
unsigned long irqflags;

switch (pipe) {
case 0:
pipestat_reg = PIPEASTAT;
interrupt = I915_DISPLAY_PIPE_A_EVENT_INTERRUPT;
break;
case 1:
pipestat_reg = PIPEBSTAT;
interrupt = I915_DISPLAY_PIPE_B_EVENT_INTERRUPT;
break;
default:
DRM_ERROR("tried to enable vblank on non-existent pipe %d\n",
pipe);
return 0;
}

spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
/* Enabling vblank events in IMR comes before PIPESTAT write, or
* there's a race where the PIPESTAT vblank bit gets set to 1, so
* the OR of enabled PIPESTAT bits goes to 1, so the PIPExEVENT in
* ISR flashes to 1, but the IIR bit doesn't get set to 1 because
* IMR masks it. It doesn't ever get set after we clear the masking
* in IMR because the ISR bit is edge, not level-triggered, on the
* OR of PIPESTAT bits.
*/
i915_enable_irq(dev_priv, interrupt);
pipestat = I915_READ(pipestat_reg);
if (IS_I965G(dev))
pipestat |= PIPE_START_VBLANK_INTERRUPT_ENABLE;
i915_enable_pipestat(dev_priv, pipe,
PIPE_START_VBLANK_INTERRUPT_ENABLE);
else
pipestat |= PIPE_VBLANK_INTERRUPT_ENABLE;
/* Clear any stale interrupt status */
pipestat |= (PIPE_START_VBLANK_INTERRUPT_STATUS |
PIPE_VBLANK_INTERRUPT_STATUS);
I915_WRITE(pipestat_reg, pipestat);
(void) I915_READ(pipestat_reg); /* Posting read */
i915_enable_pipestat(dev_priv, pipe,
PIPE_VBLANK_INTERRUPT_ENABLE);
spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);

return 0;
}

Expand All @@ -381,37 +387,12 @@ int i915_enable_vblank(struct drm_device *dev, int pipe)
void i915_disable_vblank(struct drm_device *dev, int pipe)
{
drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
u32 pipestat_reg = 0;
u32 pipestat;
u32 interrupt = 0;
unsigned long irqflags;

switch (pipe) {
case 0:
pipestat_reg = PIPEASTAT;
interrupt = I915_DISPLAY_PIPE_A_EVENT_INTERRUPT;
break;
case 1:
pipestat_reg = PIPEBSTAT;
interrupt = I915_DISPLAY_PIPE_B_EVENT_INTERRUPT;
break;
default:
DRM_ERROR("tried to disable vblank on non-existent pipe %d\n",
pipe);
return;
break;
}

spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
i915_disable_irq(dev_priv, interrupt);
pipestat = I915_READ(pipestat_reg);
pipestat &= ~(PIPE_START_VBLANK_INTERRUPT_ENABLE |
PIPE_VBLANK_INTERRUPT_ENABLE);
/* Clear any stale interrupt status */
pipestat |= (PIPE_START_VBLANK_INTERRUPT_STATUS |
PIPE_VBLANK_INTERRUPT_STATUS);
I915_WRITE(pipestat_reg, pipestat);
(void) I915_READ(pipestat_reg); /* Posting read */
i915_disable_pipestat(dev_priv, pipe,
PIPE_VBLANK_INTERRUPT_ENABLE |
PIPE_START_VBLANK_INTERRUPT_ENABLE);
spin_unlock_irqrestore(&dev_priv->user_irq_lock, irqflags);
}

Expand Down Expand Up @@ -476,32 +457,40 @@ void i915_driver_irq_preinstall(struct drm_device * dev)
drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;

I915_WRITE(HWSTAM, 0xeffe);
I915_WRITE(PIPEASTAT, 0);
I915_WRITE(PIPEBSTAT, 0);
I915_WRITE(IMR, 0xffffffff);
I915_WRITE(IER, 0x0);
(void) I915_READ(IER);
}

int i915_driver_irq_postinstall(struct drm_device *dev)
{
drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
int ret, num_pipes = 2;

/* Set initial unmasked IRQs to just the selected vblank pipes. */
dev_priv->irq_mask_reg = ~0;

ret = drm_vblank_init(dev, num_pipes);
if (ret)
return ret;

dev_priv->vblank_pipe = DRM_I915_VBLANK_PIPE_A | DRM_I915_VBLANK_PIPE_B;
dev_priv->irq_mask_reg &= ~I915_DISPLAY_PIPE_A_VBLANK_INTERRUPT;
dev_priv->irq_mask_reg &= ~I915_DISPLAY_PIPE_B_VBLANK_INTERRUPT;

dev->max_vblank_count = 0xffffff; /* only 24 bits of frame count */

dev_priv->irq_mask_reg &= I915_INTERRUPT_ENABLE_MASK;
/* Unmask the interrupts that we always want on. */
dev_priv->irq_mask_reg = ~I915_INTERRUPT_ENABLE_FIX;

dev_priv->pipestat[0] = 0;
dev_priv->pipestat[1] = 0;

/* Disable pipe interrupt enables, clear pending pipe status */
I915_WRITE(PIPEASTAT, I915_READ(PIPEASTAT) & 0x8000ffff);
I915_WRITE(PIPEBSTAT, I915_READ(PIPEBSTAT) & 0x8000ffff);
/* Clear pending interrupt status */
I915_WRITE(IIR, I915_READ(IIR));

I915_WRITE(IMR, dev_priv->irq_mask_reg);
I915_WRITE(IER, I915_INTERRUPT_ENABLE_MASK);
I915_WRITE(IMR, dev_priv->irq_mask_reg);
(void) I915_READ(IER);

opregion_enable_asle(dev);
Expand All @@ -513,21 +502,19 @@ int i915_driver_irq_postinstall(struct drm_device *dev)
void i915_driver_irq_uninstall(struct drm_device * dev)
{
drm_i915_private_t *dev_priv = (drm_i915_private_t *) dev->dev_private;
u32 temp;

if (!dev_priv)
return;

dev_priv->vblank_pipe = 0;

I915_WRITE(HWSTAM, 0xffffffff);
I915_WRITE(PIPEASTAT, 0);
I915_WRITE(PIPEBSTAT, 0);
I915_WRITE(IMR, 0xffffffff);
I915_WRITE(IER, 0x0);

temp = I915_READ(PIPEASTAT);
I915_WRITE(PIPEASTAT, temp);
temp = I915_READ(PIPEBSTAT);
I915_WRITE(PIPEBSTAT, temp);
temp = I915_READ(IIR);
I915_WRITE(IIR, temp);
I915_WRITE(PIPEASTAT, I915_READ(PIPEASTAT) & 0x8000ffff);
I915_WRITE(PIPEBSTAT, I915_READ(PIPEBSTAT) & 0x8000ffff);
I915_WRITE(IIR, I915_READ(IIR));
}
18 changes: 8 additions & 10 deletions drivers/gpu/drm/i915/i915_opregion.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -235,17 +235,15 @@ void opregion_enable_asle(struct drm_device *dev)
struct opregion_asle *asle = dev_priv->opregion.asle;

if (asle) {
u32 pipeb_stats = I915_READ(PIPEBSTAT);
if (IS_MOBILE(dev)) {
/* Many devices trigger events with a write to the
legacy backlight controller, so we need to ensure
that it's able to generate interrupts */
I915_WRITE(PIPEBSTAT, pipeb_stats |=
I915_LEGACY_BLC_EVENT_ENABLE);
i915_enable_irq(dev_priv, I915_ASLE_INTERRUPT |
I915_DISPLAY_PIPE_B_EVENT_INTERRUPT);
} else
i915_enable_irq(dev_priv, I915_ASLE_INTERRUPT);
unsigned long irqflags;

spin_lock_irqsave(&dev_priv->user_irq_lock, irqflags);
i915_enable_pipestat(dev_priv, 1,
I915_LEGACY_BLC_EVENT_ENABLE);
spin_unlock_irqrestore(&dev_priv->user_irq_lock,
irqflags);
}

asle->tche = ASLE_ALS_EN | ASLE_BLC_EN | ASLE_PFIT_EN |
ASLE_PFMB_EN;
Expand Down

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