[PATCH 3/6] drm/i915: Error out if we are trying to use VGA with SPLL already in use

From: Damien Lespiau <damien.lespiau@intel.com>
To: intel-gfx@lists.freedesktop.org
Subject: [PATCH 3/6] drm/i915: Error out if we are trying to use VGA with SPLL already in use
Date: Thu,  7 Mar 2013 15:30:25 +0000	[thread overview]
Message-ID: <1362670228-19494-3-git-send-email-damien.lespiau@intel.com> (raw)
In-Reply-To: <1362670228-19494-1-git-send-email-damien.lespiau@intel.com>

Our static analysis tool noticed that 'reg' could be used uninitialized if
we are trying to get a PLL to drive VGA and SPLL is already in use
(plls->spll_refcoung != 0).

In the (error) case above, let's return false to the caller and emit an
error.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
---
 drivers/gpu/drm/i915/intel_ddi.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index a1505e3..0eab200 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -898,6 +898,9 @@ bool intel_ddi_pll_mode_set(struct drm_crtc *crtc, int clock)
 			plls->spll_refcount++;
 			reg = SPLL_CTL;
 			intel_crtc->ddi_pll_sel = PORT_CLK_SEL_SPLL;
+		} else {
+			DRM_ERROR("SPLL already in use\n");
+			return false;
 		}
 
 		WARN(I915_READ(reg) & SPLL_PLL_ENABLE,
-- 
1.7.7.5
