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-rw-r--r--drivers/gpu/drm/radeon/atombios_crtc.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index 8c2d6478a221..3271b5a3421f 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -527,6 +527,20 @@ static u32 atombios_adjust_pll(struct drm_crtc *crtc,
pll->algo = PLL_ALGO_LEGACY;
pll->flags |= RADEON_PLL_PREFER_CLOSEST_LOWER;
}
+ /* There is some evidence (often anecdotal) that RV515 LVDS
+ * (on some boards at least) prefers the legacy algo. I'm not
+ * sure whether this should handled generically or on a
+ * case-by-case quirk basis. Both algos should work fine in the
+ * majority of cases.
+ */
+ if ((radeon_encoder->active_device & (ATOM_DEVICE_LCD_SUPPORT)) &&
+ (rdev->family == CHIP_RV515)) {
+ /* allow the user to overrride just in case */
+ if (radeon_new_pll == 1)
+ pll->algo = PLL_ALGO_NEW;
+ else
+ pll->algo = PLL_ALGO_LEGACY;
+ }
} else {
if (encoder->encoder_type != DRM_MODE_ENCODER_DAC)
pll->flags |= RADEON_PLL_NO_ODD_POST_DIV;