[Intel-gfx] [PATCH] drm/i915: Fix erroneous conversion to u8

[Damien Lespiau]

adj was defined as u8. The issue is last_adj can be negative and adj is
initialized with:

  adj = dev_priv->rps.last_adj;

and we were also happily doing things like:

  if (adj < 0)

(thank static analysers!)

v2: Make new_delay an int in case we overflow the u8 in the intermediate
    computations. new_delay will get clamped at the end anyway. (Ville)

Cc: Deepak S <deepak.s at linux.intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
---
 drivers/gpu/drm/i915/i915_irq.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 9fdf738..8e6729e 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -1327,10 +1327,10 @@ static u32 vlv_c0_residency(struct drm_i915_private *dev_priv,
  * @dev_priv: DRM device private
  *
  */
-static u32 vlv_calc_delay_from_C0_counters(struct drm_i915_private *dev_priv)
+static int vlv_calc_delay_from_C0_counters(struct drm_i915_private *dev_priv)
 {
 	u32 residency_C0_up = 0, residency_C0_down = 0;
-	u8 new_delay, adj;
+	int new_delay, adj;
 
 	dev_priv->rps.ei_interrupt_count++;
 
-- 
1.8.3.1