[PATCH v5] drm/radeon: fix internal display on iMac11, 1 (RV770/DCE3.1)

[Gilles Risch <gilles.risch@gmail.com>]

The Apple iMac11,1 (27-inch, Late 2009) uses a Mobility Radeon HD 4850
(RV770/DCE3.1) with a 2560x1440 internal panel on an internal
DisplayPort path. Without this fix the display stays dark under KMS.

This machine suffers from the same issue as iMac10,1 and iMac11,2:
Apple routes the internal display through Link B of the DIG encoder
instead of Link A. Add iMac11,1 to the existing DMI quirk and move
the Apple-specific encoder assignment into its own block, independent
of the DCE version check.

Additionally, the 2560x1440 panel requires RADEON_PLL_USE_FRAC_FB_DIV
and ATOM_ENCODER_CMD_DP_VIDEO_ON, limited to iMac11,1 via dmi_match()
to avoid affecting other boards.

Signed-off-by: Gilles Risch <gilles.risch@gmail.com>
---
 drivers/gpu/drm/radeon/atombios_crtc.c     |  5 ++++-
 drivers/gpu/drm/radeon/atombios_encoders.c | 23 ++++++++++++----------
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index 2fc0334e0..075eba2d4 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -24,6 +24,8 @@
  *          Alex Deucher
  */
 
+#include <linux/dmi.h>
+
 #include <drm/drm_fixed.h>
 #include <drm/drm_fourcc.h>
 #include <drm/drm_framebuffer.h>
@@ -594,7 +596,8 @@ static u32 atombios_adjust_pll(struct drm_crtc *crtc,
 		if (((rdev->family == CHIP_RS780) || (rdev->family == CHIP_RS880))
 		    && !radeon_crtc->ss_enabled)
 			radeon_crtc->pll_flags |= RADEON_PLL_USE_FRAC_FB_DIV;
-		if (ASIC_IS_DCE32(rdev) && mode->clock > 165000)
+		if ((ASIC_IS_DCE32(rdev) || dmi_match(DMI_PRODUCT_NAME, "iMac11,1"))
+		    && mode->clock > 165000)
 			radeon_crtc->pll_flags |= RADEON_PLL_USE_FRAC_FB_DIV;
 	} else {
 		radeon_crtc->pll_flags |= RADEON_PLL_LEGACY;
diff --git a/drivers/gpu/drm/radeon/atombios_encoders.c b/drivers/gpu/drm/radeon/atombios_encoders.c
index 5cfd8fcfa..8b3f8303a 100644
--- a/drivers/gpu/drm/radeon/atombios_encoders.c
+++ b/drivers/gpu/drm/radeon/atombios_encoders.c
@@ -1707,7 +1707,7 @@ radeon_atom_encoder_dpms_dig(struct drm_encoder *encoder, int mode)
 		if (ENCODER_MODE_IS_DP(atombios_get_encoder_mode(encoder)) && connector) {
 			/* DP_SET_POWER_D0 is set in radeon_dp_link_train */
 			radeon_dp_link_train(encoder, connector);
-			if (ASIC_IS_DCE4(rdev))
+			if (ASIC_IS_DCE4(rdev) || dmi_match(DMI_PRODUCT_NAME, "iMac11,1"))
 				atombios_dig_encoder_setup(encoder, ATOM_ENCODER_CMD_DP_VIDEO_ON, 0);
 		}
 		if (radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT)) {
@@ -2123,17 +2123,20 @@ int radeon_atom_pick_dig_encoder(struct drm_encoder *encoder, int fe_idx)
 	}
 
 	/*
-	 * On DCE32 any encoder can drive any block so usually just use crtc id,
-	 * but Apple thinks different at least on iMac10,1 and iMac11,2, so there use linkb,
-	 * otherwise the internal eDP panel will stay dark.
+	 * Apple routes the internal eDP panel through Link B of the DIG encoder
+	 * instead of Link A on the iMac10,1, iMac11,1 and iMac11,2.
+	 * Use linkb to avoid a dark display.
 	 */
-	if (ASIC_IS_DCE32(rdev)) {
-		if (dmi_match(DMI_PRODUCT_NAME, "iMac10,1") ||
-		    dmi_match(DMI_PRODUCT_NAME, "iMac11,2"))
-			enc_idx = (dig->linkb) ? 1 : 0;
-		else
-			enc_idx = radeon_crtc->crtc_id;
+	if (dmi_match(DMI_PRODUCT_NAME, "iMac10,1") ||
+	    dmi_match(DMI_PRODUCT_NAME, "iMac11,1") ||
+	    dmi_match(DMI_PRODUCT_NAME, "iMac11,2")) {
+		enc_idx = (dig->linkb) ? 1 : 0;
+		goto assigned;
+	}
 
+	/* on DCE32 and encoder can driver any block so just crtc id */
+	if (ASIC_IS_DCE32(rdev)) {
+		enc_idx = radeon_crtc->crtc_id;
 		goto assigned;
 	}
 
-- 
2.47.3