drm/radeon/kms/atom: Fix DVO support

DVO in 12 bit mode (which seems to be the most common
config) requires 2x ppll.

Fixes fdo bug 21857.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index e5a3c301b7a9..8516e1b2329a 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -483,8 +483,14 @@ void atombios_crtc_set_pll(struct drm_crtc *crtc, struct drm_display_mode *mode)
                 atom_execute_table(rdev->mode_info.atom_context,
                                    index, (uint32_t *)&adjust_pll_args);
                 adjusted_clock = le16_to_cpu(adjust_pll_args.usPixelClock) * 10;
-        } else
-                adjusted_clock = mode->clock;
+        } else {
+                /* DVO wants 2x pixel clock if the DVO chip is in 12 bit mode */
+                if (ASIC_IS_AVIVO(rdev) &&
+                    (radeon_encoder->encoder_id == ENCODER_OBJECT_ID_INTERNAL_KLDSCP_DVO1))
+                        adjusted_clock = mode->clock * 2;
+                else
+                        adjusted_clock = mode->clock;
+        }
 
         if (radeon_crtc->crtc_id == 0)
                 pll = &rdev->clock.p1pll;