drm/nouveau: Fix up pre-nv17 analog load detection.

Signed-off-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/gpu/drm/nouveau/nv04_dac.c b/drivers/gpu/drm/nouveau/nv04_dac.c
index d0e038d28948..1d73b15d70da 100644
--- a/drivers/gpu/drm/nouveau/nv04_dac.c
+++ b/drivers/gpu/drm/nouveau/nv04_dac.c
@@ -119,7 +119,7 @@ static enum drm_connector_status nv04_dac_detect(struct drm_encoder *encoder,
                                                  struct drm_connector *connector)
 {
         struct drm_device *dev = encoder->dev;
-        uint8_t saved_seq1, saved_pi, saved_rpc1;
+        uint8_t saved_seq1, saved_pi, saved_rpc1, saved_cr_mode;
         uint8_t saved_palette0[3], saved_palette_mask;
         uint32_t saved_rtest_ctrl, saved_rgen_ctrl;
         int i;
@@ -135,6 +135,9 @@ static enum drm_connector_status nv04_dac_detect(struct drm_encoder *encoder,
                 /* only implemented for head A for now */
                 NVSetOwner(dev, 0);
 
+        saved_cr_mode = NVReadVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX);
+        NVWriteVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX, saved_cr_mode | 0x80);
+
         saved_seq1 = NVReadVgaSeq(dev, 0, NV_VIO_SR_CLOCK_INDEX);
         NVWriteVgaSeq(dev, 0, NV_VIO_SR_CLOCK_INDEX, saved_seq1 & ~0x20);
 
@@ -203,6 +206,7 @@ out:
         NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_PIXEL_INDEX, saved_pi);
         NVWriteVgaCrtc(dev, 0, NV_CIO_CRE_RPC1_INDEX, saved_rpc1);
         NVWriteVgaSeq(dev, 0, NV_VIO_SR_CLOCK_INDEX, saved_seq1);
+        NVWriteVgaCrtc(dev, 0, NV_CIO_CR_MODE_INDEX, saved_cr_mode);
 
         if (blue == 0x18) {
                 NV_INFO(dev, "Load detected on head A\n");