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path: root/drivers/gpu/drm/i915/intel_sideband.c
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Diffstat (limited to 'drivers/gpu/drm/i915/intel_sideband.c')
-rw-r--r--drivers/gpu/drm/i915/intel_sideband.c20
1 files changed, 16 insertions, 4 deletions
diff --git a/drivers/gpu/drm/i915/intel_sideband.c b/drivers/gpu/drm/i915/intel_sideband.c
index 9f782b5..7d971cb 100644
--- a/drivers/gpu/drm/i915/intel_sideband.c
+++ b/drivers/gpu/drm/i915/intel_sideband.c
@@ -216,6 +216,7 @@ u32 intel_sbi_read(struct drm_i915_private *dev_priv, u16 reg,
}
I915_WRITE(SBI_ADDR, (reg << 16));
+ I915_WRITE(SBI_DATA, 0);
if (destination == SBI_ICLK)
value = SBI_CTL_DEST_ICLK | SBI_CTL_OP_CRRD;
@@ -225,10 +226,15 @@ u32 intel_sbi_read(struct drm_i915_private *dev_priv, u16 reg,
if (intel_wait_for_register(dev_priv,
SBI_CTL_STAT,
- SBI_BUSY | SBI_RESPONSE_FAIL,
+ SBI_BUSY,
0,
100)) {
- DRM_ERROR("timeout waiting for SBI to complete read transaction\n");
+ DRM_ERROR("timeout waiting for SBI to complete read\n");
+ return 0;
+ }
+
+ if (I915_READ(SBI_CTL_STAT) & SBI_RESPONSE_FAIL) {
+ DRM_ERROR("error during SBI read of reg %x\n", reg);
return 0;
}
@@ -260,10 +266,16 @@ void intel_sbi_write(struct drm_i915_private *dev_priv, u16 reg, u32 value,
if (intel_wait_for_register(dev_priv,
SBI_CTL_STAT,
- SBI_BUSY | SBI_RESPONSE_FAIL,
+ SBI_BUSY,
0,
100)) {
- DRM_ERROR("timeout waiting for SBI to complete write transaction\n");
+ DRM_ERROR("timeout waiting for SBI to complete write\n");
+ return;
+ }
+
+ if (I915_READ(SBI_CTL_STAT) & SBI_RESPONSE_FAIL) {
+ DRM_ERROR("error during SBI write of %x to reg %x\n",
+ value, reg);
return;
}
}
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