--- a/content/svg/content/src/nsSVGFilters.cpp
+++ b/content/svg/content/src/nsSVGFilters.cpp
@@ -95,16 +95,26 @@ CopyRect(const nsSVGFE::Image* aDest, co
   NS_ASSERTION(aDest->mImage->GetSize() == aSrc->mImage->GetSize(), "size mismatch");
   NS_ASSERTION(nsIntRect(0, 0, aDest->mImage->Width(), aDest->mImage->Height()).Contains(aDataRect),
                "aDataRect out of bounds");
 
   CopyDataRect(aDest->mImage->Data(), aSrc->mImage->Data(),
                aSrc->mImage->Stride(), aDataRect);
 }
 
+static void
+CopyAndScaleDeviceOffset(const gfxImageSurface *aImage, gfxImageSurface *aResult,
+                         gfxFloat kernelX, gfxFloat kernelY)
+{
+  gfxPoint deviceOffset = aImage->GetDeviceOffset();
+  deviceOffset.x /= kernelX;
+  deviceOffset.y /= kernelY;
+  aResult->SetDeviceOffset(deviceOffset);
+}
+
 //--------------------Filter Element Base Class-----------------------
 
 nsSVGElement::LengthInfo nsSVGFE::sLengthInfo[4] =
 {
   { &nsGkAtoms::x, 0, nsIDOMSVGLength::SVG_LENGTHTYPE_PERCENTAGE, nsSVGUtils::X },
   { &nsGkAtoms::y, 0, nsIDOMSVGLength::SVG_LENGTHTYPE_PERCENTAGE, nsSVGUtils::Y },
   { &nsGkAtoms::width, 100, nsIDOMSVGLength::SVG_LENGTHTYPE_PERCENTAGE, nsSVGUtils::X },
   { &nsGkAtoms::height, 100, nsIDOMSVGLength::SVG_LENGTHTYPE_PERCENTAGE, nsSVGUtils::Y }
@@ -176,16 +186,20 @@ nsSVGFE::SetupScalingFilter(nsSVGFilterI
   result.mTarget = new gfxImageSurface(scaledSize,
                                        gfxASurface::ImageFormatARGB32);
   if (!result.mSource || result.mSource->CairoStatus() ||
       !result.mTarget || result.mTarget->CairoStatus()) {
     result.mSource = nsnull;
     result.mTarget = nsnull;
     return result;
   }
+
+  CopyAndScaleDeviceOffset(aSource->mImage, result.mSource, kernelX, kernelY);
+  CopyAndScaleDeviceOffset(aTarget->mImage, result.mTarget, kernelX, kernelY);
+
   result.mRealTarget = aTarget->mImage;
 
   gfxContext ctx(result.mSource);
   ctx.SetOperator(gfxContext::OPERATOR_SOURCE);
   ctx.Scale(double(scaledSize.width) / aTarget->mImage->Width(),
             double(scaledSize.height) / aTarget->mImage->Height());
   ctx.SetSource(aSource->mImage);
   ctx.Paint();

new file mode 100644
--- /dev/null
+++ b/layout/reftests/svg/filters/filter-kernelUnitLength-01-ref.svg
@@ -0,0 +1,15 @@
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+  <defs>
+    <filter id="emboss">
+      <feGaussianBlur in="SourceAlpha" stdDeviation="3" result="blur"/>
+      <!-- without kernelUnitLength attribute -->
+      <feSpecularLighting in="blur" result="spec" surfaceScale="-3"
+                          specularConstant="2" specularExponent="16"
+                          lighting-color="#ffb155">
+        <feDistantLight azimuth="45" elevation="45"/>
+      </feSpecularLighting>
+      <feComposite in="spec" in2="SourceGraphic" operator="in" result="specOut"/>
+    </filter>
+  </defs>
+  <path filter="url(#emboss)" d="M 44.408917,5.7095287 C 535.13945,101.91182 534.01725,101.52506 532.53904,101.52499 C 531.36871,101.52506 530.17420,101.85117 528.96683,102.49024 z "/>
+</svg>

new file mode 100644
--- /dev/null
+++ b/layout/reftests/svg/filters/filter-kernelUnitLength-01.svg
@@ -0,0 +1,15 @@
+<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+  <defs>
+    <filter id="emboss">
+      <feGaussianBlur in="SourceAlpha" stdDeviation="3" result="blur"/>
+      <!-- with kernelUnitLength attribute -->
+      <feSpecularLighting in="blur" result="spec" surfaceScale="-3"
+                          specularConstant="2" specularExponent="16"
+                          lighting-color="#ffb155" kernelUnitLength="1">
+        <feDistantLight azimuth="45" elevation="45"/>
+      </feSpecularLighting>
+      <feComposite in="spec" in2="SourceGraphic" operator="in" result="specOut"/>
+    </filter>
+  </defs>
+  <path filter="url(#emboss)" d="M 44.408917,5.7095287 C 535.13945,101.91182 534.01725,101.52506 532.53904,101.52499 C 531.36871,101.52506 530.17420,101.85117 528.96683,102.49024 z "/>
+</svg>

--- a/layout/reftests/svg/filters/reftest.list
+++ b/layout/reftests/svg/filters/reftest.list
@@ -49,16 +49,17 @@
 == filter-clipped-rect-01.svg pass.svg
 == filter-filterRes-high-01.svg pass.svg
 == filter-filterRes-high-02.svg pass.svg
 random-if(d2d) == filter-filterRes-low-01.svg pass.svg
 == filter-inner-svg-01.svg pass.svg
 == filter-inner-svg-02.svg pass.svg
 == filter-inner-svg-03.svg pass.svg
 fails == filter-marked-line-01.svg pass.svg # bug 477704
+== filter-kernelUnitLength-01.svg filter-kernelUnitLength-01-ref.svg
 == filter-marked-line-02.svg pass.svg
 == filter-marked-line-03.svg pass.svg
 == filter-marked-line-04.svg pass.svg
 == filter-marked-line-05.svg pass.svg
 == filter-marked-line-06.svg pass.svg
 == filter-marked-line-07.svg pass.svg
 == filter-marked-line-08.svg pass.svg
 == filter-marked-line-09.svg pass.svg