drm/i915: Avoid compiler warning for maybe unused gu_misc_iir

/kisskb/src/drivers/gpu/drm/i915/i915_irq.c: warning: 'gu_misc_iir' may be used uninitialized in this function [-Wuninitialized]:  => 3120:10

Silence the compiler warning by ensuring that the local variable is
initialised and removing the guard that is confusing the older gcc.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Fixes: df0d28c185ad ("drm/i915/icl: GSE interrupt moves from DE_MISC to GU_MISC")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180926104718.17462-1-chris@chris-wilson.co.uk

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 10f28a2ee2e6f5ac93f5a144b4fda52f4a2f78c0..2e242270e270865ca2f1cc0db2ebbf03dac11185 100644 (file)
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -3088,36 +3088,27 @@ gen11_gt_irq_handler(struct drm_i915_private * const i915,
        spin_unlock(&i915->irq_lock);
 }
 
-static void
-gen11_gu_misc_irq_ack(struct drm_i915_private *dev_priv, const u32 master_ctl,
-                     u32 *iir)
+static u32
+gen11_gu_misc_irq_ack(struct drm_i915_private *dev_priv, const u32 master_ctl)
 {
        void __iomem * const regs = dev_priv->regs;
+       u32 iir;
 
        if (!(master_ctl & GEN11_GU_MISC_IRQ))
-               return;
+               return 0;
+
+       iir = raw_reg_read(regs, GEN11_GU_MISC_IIR);
+       if (likely(iir))
+               raw_reg_write(regs, GEN11_GU_MISC_IIR, iir);
 
-       *iir = raw_reg_read(regs, GEN11_GU_MISC_IIR);
-       if (likely(*iir))
-               raw_reg_write(regs, GEN11_GU_MISC_IIR, *iir);
+       return iir;
 }
 
 static void
-gen11_gu_misc_irq_handler(struct drm_i915_private *dev_priv,
-                         const u32 master_ctl, const u32 iir)
+gen11_gu_misc_irq_handler(struct drm_i915_private *dev_priv, const u32 iir)
 {
-       if (!(master_ctl & GEN11_GU_MISC_IRQ))
-               return;
-
-       if (unlikely(!iir)) {
-               DRM_ERROR("GU_MISC iir blank!\n");
-               return;
-       }
-
        if (iir & GEN11_GU_MISC_GSE)
                intel_opregion_asle_intr(dev_priv);
-       else
-               DRM_ERROR("Unexpected GU_MISC interrupt 0x%x\n", iir);
 }
 
 static irqreturn_t gen11_irq_handler(int irq, void *arg)
@@ -3154,12 +3145,12 @@ static irqreturn_t gen11_irq_handler(int irq, void *arg)
                enable_rpm_wakeref_asserts(i915);
        }
 
-       gen11_gu_misc_irq_ack(i915, master_ctl, &gu_misc_iir);
+       gu_misc_iir = gen11_gu_misc_irq_ack(i915, master_ctl);
 
        /* Acknowledge and enable interrupts. */
        raw_reg_write(regs, GEN11_GFX_MSTR_IRQ, GEN11_MASTER_IRQ | master_ctl);
 
-       gen11_gu_misc_irq_handler(i915, master_ctl, gu_misc_iir);
+       gen11_gu_misc_irq_handler(i915, gu_misc_iir);
 
        return IRQ_HANDLED;
 }