Attachment 60601 Details for Bug 44006 – Always unsuppress down interrupts

[patch] Always unsuppress down interrupts

0001-drm-i915-Always-unsuppress-down-interrupts-when-prog.patch (text/plain), 3.52 KB, created by Chris Wilson on 2012-04-26 01:26:13 UTC

(hide)

Description:

Filename:

MIME Type:

Creator: Chris Wilson

Created: 2012-04-26 01:26:13 UTC

Size: 3.52 KB

patch

obsolete

>From b1fffd1a2587578bf0d238c37de80444f044bf30 Mon Sep 17 00:00:00 2001
>From: Chris Wilson <chris@chris-wilson.co.uk>
>Date: Wed, 25 Apr 2012 19:09:39 +0100
>Subject: [PATCH] drm/i915: Always unsuppress down-interrupts when programming
> a non-min value
>
>The GT power programing guide recommends always unsuppressing the down
>interrupt when programming any render frequency above the minimum. This
>is because the GT unit doesn't emit interrupts whilst it is asleep which
>can lead to the down interrupt being lost. Also due to our own
>coalescing of interrupts through use of a bottom-half, it looks safer to
>always rewrite the limits.
>
>Also note that in the original code we never wrote the Pn value to
>suppress down interrupts as the new_delay would never be decremented
>past min_delay. Further confusion abounds.
>
>References: https://bugs.freedesktop.org/show_bug.cgi?id=44006
>Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
>Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
>---
> drivers/gpu/drm/i915/i915_irq.c |   41 +++++++++++++++++++++------------------
> 1 file changed, 22 insertions(+), 19 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
>index 13d40a1..bdfe6d4 100644
>--- a/drivers/gpu/drm/i915/i915_irq.c
>+++ b/drivers/gpu/drm/i915/i915_irq.c
>@@ -382,8 +382,8 @@ static void gen6_pm_rps_work(struct work_struct *work)
> {
> 	drm_i915_private_t *dev_priv = container_of(work, drm_i915_private_t,
> 						    rps_work);
>-	u8 new_delay = dev_priv->cur_delay;
> 	u32 pm_iir, pm_imr;
>+	u32 limits, new_delay;
> 
> 	spin_lock_irq(&dev_priv->rps_lock);
> 	pm_iir = dev_priv->pm_iir;
>@@ -392,36 +392,39 @@ static void gen6_pm_rps_work(struct work_struct *work)
> 	I915_WRITE(GEN6_PMIMR, 0);
> 	spin_unlock_irq(&dev_priv->rps_lock);
> 
>-	if (!pm_iir)
>+	if ((pm_iir & GEN6_PM_DEFERRED_EVENTS) == 0)
> 		return;
> 
> 	mutex_lock(&dev_priv->dev->struct_mutex);
>+
>+	gen6_gt_force_wake_get(dev_priv);
>+	limits = I915_READ(GEN6_RP_INTERRUPT_LIMITS);
>+
>+	/* Make sure we continue to get interrupts
>+	 * until we hit the minimum or maximum frequencies.
>+	 */
>+	limits &= ~(0x3f << 16 | 0x3f << 24);
>+
> 	if (pm_iir & GEN6_PM_RP_UP_THRESHOLD) {
>-		if (dev_priv->cur_delay != dev_priv->max_delay)
>-			new_delay = dev_priv->cur_delay + 1;
>-		if (new_delay > dev_priv->max_delay)
>+		new_delay = dev_priv->cur_delay + 1;
>+		if (new_delay >= dev_priv->max_delay)
> 			new_delay = dev_priv->max_delay;
>-	} else if (pm_iir & (GEN6_PM_RP_DOWN_THRESHOLD | GEN6_PM_RP_DOWN_TIMEOUT)) {
>-		gen6_gt_force_wake_get(dev_priv);
>-		if (dev_priv->cur_delay != dev_priv->min_delay)
>-			new_delay = dev_priv->cur_delay - 1;
>-		if (new_delay < dev_priv->min_delay) {
>+		else
>+			limits |= (dev_priv->max_delay & 0x3f) << 24;
>+	} else {
>+		new_delay = dev_priv->cur_delay - 1;
>+		if (new_delay <= dev_priv->min_delay) {
> 			new_delay = dev_priv->min_delay;
>-			I915_WRITE(GEN6_RP_INTERRUPT_LIMITS,
>-				   I915_READ(GEN6_RP_INTERRUPT_LIMITS) |
>-				   ((new_delay << 16) & 0x3f0000));
>-		} else {
>-			/* Make sure we continue to get down interrupts
>-			 * until we hit the minimum frequency */
>-			I915_WRITE(GEN6_RP_INTERRUPT_LIMITS,
>-				   I915_READ(GEN6_RP_INTERRUPT_LIMITS) & ~0x3f0000);
>+			limits |= (new_delay & 0x3f) << 16;
> 		}
>-		gen6_gt_force_wake_put(dev_priv);
> 	}
> 
> 	gen6_set_rps(dev_priv->dev, new_delay);
> 	dev_priv->cur_delay = new_delay;
> 
>+	I915_WRITE(GEN6_RP_INTERRUPT_LIMITS, limits);
>+	gen6_gt_force_wake_put(dev_priv);
>+
> 	/*
> 	 * rps_lock not held here because clearing is non-destructive. There is
> 	 * an *extremely* unlikely race with gen6_rps_enable() that is prevented
>-- 
>1.7.10
>

Actions: View | Splinter Review

Attachments on bug 44006: 54669 | 54671 | 54695 | 54696 | 54781 | 54782 | 58796 | 58797 | 58798 | 60586 | 60601 | 60602 | 60603 | 60605 | 60664

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.