From 5190707e7a4fc701e94cd7e152d15dbba90b63ff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@linux.intel.com>
Date: Fri, 18 Aug 2017 21:37:02 +0300
Subject: [PATCH] drm/i915: Gen3 HWSTAM is actually 32 bits
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Git-commit: 5190707e7a4fc701e94cd7e152d15dbba90b63ff
Patch-mainline: v4.15-rc1
References: FATE#322643 bsc#1055900

Bspec claims that HWSTAM is only 16 bits on gen3, but the other
interrupts registers are 32 bits and there are 18 valid interrupt
bits. Hence a 16 bit HWSTAM wouldn't be able to contain all the
bits, so it seems the spec is incorrect about the size of the
register. And indeed I can clear bits 16 and 17 just fine with
a 32 bit write. So let's adjust the code to treat the register
as 32 bits.

Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170818183705.27850-14-ville.syrjala@linux.intel.com
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/i915/i915_irq.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -3752,7 +3752,7 @@ static void i915_irq_preinstall(struct d
 
 	i9xx_pipestat_irq_reset(dev_priv);
 
-	I915_WRITE16(HWSTAM, 0xeffe);
+	I915_WRITE(HWSTAM, 0xffffeffe);
 
 	GEN3_IRQ_RESET();
 }
@@ -3859,7 +3859,7 @@ static void i915_irq_uninstall(struct dr
 
 	i9xx_pipestat_irq_reset(dev_priv);
 
-	I915_WRITE16(HWSTAM, 0xffff);
+	I915_WRITE(HWSTAM, 0xffffffff);
 
 	GEN3_IRQ_RESET();
 }