[RESEND PATCH 01/28] drm/gma500: Sanity-check pipe index

[Boris Brezillon]

From: Thierry Reding <tred...@nvidia.com>

If the DSI output isn't connected, then mdfld_dsi_encoder_get_pipe()
will return -1. The mdfld_dsi_dp_mode_set() function doesn't properly
check for this condition and causes the following compiler warnings:

          CC      drivers/gpu/drm/gma500/mdfld_dsi_dpi.o
        drivers/gpu/drm/gma500/mdfld_dsi_dpi.c: In function 
‘mdfld_dsi_dpi_mode_set’:
        drivers/gpu/drm/gma500/mdfld_dsi_dpi.c:828:35: warning: array subscript 
is below array bounds [-Warray-bounds]
          u32 pipeconf = dev_priv->pipeconf[pipe];
                                           ^
        drivers/gpu/drm/gma500/mdfld_dsi_dpi.c:829:33: warning: array subscript 
is below array bounds [-Warray-bounds]
          u32 dspcntr = dev_priv->dspcntr[pipe];
                                         ^

Fix this by checking for a valid pipe before indexing the pipeconf and
dspcntr arrays.

Cc: Patrik Jakobsson <patrik.r.jakobsson at gmail.com>
Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson at gmail.com>
Signed-off-by: Thierry Reding <treding at nvidia.com>
---
 drivers/gpu/drm/gma500/mdfld_dsi_dpi.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/gma500/mdfld_dsi_dpi.c 
b/drivers/gpu/drm/gma500/mdfld_dsi_dpi.c
index 1a1acd3..7cd87a0 100644
--- a/drivers/gpu/drm/gma500/mdfld_dsi_dpi.c
+++ b/drivers/gpu/drm/gma500/mdfld_dsi_dpi.c
@@ -821,14 +821,18 @@ void mdfld_dsi_dpi_mode_set(struct drm_encoder *encoder,
        struct drm_device *dev = dsi_config->dev;
        struct drm_psb_private *dev_priv = dev->dev_private;
        int pipe = mdfld_dsi_encoder_get_pipe(dsi_encoder);
-
        u32 pipeconf_reg = PIPEACONF;
        u32 dspcntr_reg = DSPACNTR;
+       u32 pipeconf, dspcntr;

-       u32 pipeconf = dev_priv->pipeconf[pipe];
-       u32 dspcntr = dev_priv->dspcntr[pipe];
        u32 mipi = MIPI_PORT_EN | PASS_FROM_SPHY_TO_AFE | SEL_FLOPPED_HSTX;

+       if (WARN_ON(pipe < 0))
+               return;
+
+       pipeconf = dev_priv->pipeconf[pipe];
+       dspcntr = dev_priv->dspcntr[pipe];
+
        if (pipe) {
                pipeconf_reg = PIPECCONF;
                dspcntr_reg = DSPCCNTR;
-- 
2.1.4