drm/nvc0/fifo: ignore bits in PFIFO_INTR that aren't set in PFIFO_INTR_EN

PFIFO_INTR = 0x40000000 appears to be a normal case on nvc0/nve0 PFIFO,
the binary driver appears to completely ignore it in its PFIFO interrupt
handler and even masks off the bit (as we do) in PFIFO_INTR_EN at init
time.

The bits still light up in the hardware sometimes though, so lets just
ignore any bits we haven't explicitely requested.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

2 files changed, 4 insertions, 2 deletions

diff --git a/drivers/gpu/drm/nouveau/nvc0_fifo.c b/drivers/gpu/drm/nouveau/nvc0_fifo.c
index 7d85553d518c..cd39eb99f5b1 100644
--- a/drivers/gpu/drm/nouveau/nvc0_fifo.c
+++ b/drivers/gpu/drm/nouveau/nvc0_fifo.c
@@ -373,7 +373,8 @@ nvc0_fifo_isr_subfifo_intr(struct drm_device *dev, int unit)
 static void
 nvc0_fifo_isr(struct drm_device *dev)
 {
-        u32 stat = nv_rd32(dev, 0x002100);
+        u32 mask = nv_rd32(dev, 0x002140);
+        u32 stat = nv_rd32(dev, 0x002100) & mask;
 
         if (stat & 0x00000100) {
                 NV_INFO(dev, "PFIFO: unknown status 0x00000100\n");
diff --git a/drivers/gpu/drm/nouveau/nve0_fifo.c b/drivers/gpu/drm/nouveau/nve0_fifo.c
index e98d144e6eb9..281bece751b6 100644
--- a/drivers/gpu/drm/nouveau/nve0_fifo.c
+++ b/drivers/gpu/drm/nouveau/nve0_fifo.c
@@ -345,7 +345,8 @@ nve0_fifo_isr_subfifo_intr(struct drm_device *dev, int unit)
 static void
 nve0_fifo_isr(struct drm_device *dev)
 {
-        u32 stat = nv_rd32(dev, 0x002100);
+        u32 mask = nv_rd32(dev, 0x002140);
+        u32 stat = nv_rd32(dev, 0x002100) & mask;
 
         if (stat & 0x00000100) {
                 NV_INFO(dev, "PFIFO: unknown status 0x00000100\n");