Re: [PATCH] drm/radeon: fix eDP resume from suspend on iMac11, 1 / DCE3.1 systems

[Alex Deucher <alexdeucher@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 2843 bytes --]

On Sat, May 16, 2026 at 2:52 PM Gilles Risch <gilles.risch@gmail.com> wrote:
>
> After suspend/resume the internal eDP display on iMac11,1 (and
> potentially other DCE3.1 systems) stays dark because
> atombios_set_edp_panel_power() skips panel power control for
> anything older than DCE4.
>
> Fix this by:
> - Extending atombios_set_edp_panel_power() to also handle DCE3.1
>   by changing the !ASIC_IS_DCE4() guard to !ASIC_IS_DCE31().
>   HPD polling works correctly on DCE3.1 (verified: HPD is asserted
>   at iteration 0 on iMac11,1).
> - Issuing ATOM_ENCODER_CMD_DP_VIDEO_ON/OFF for DCE3.1 in addition
>   to DCE4+.
>
> Tested on iMac11,1 (Mobility Radeon HD 4850, RV770/DCE3.1).
>
> Signed-off-by: Gilles Risch <gilles.risch@gmail.com>
> ---
>  drivers/gpu/drm/radeon/atombios_encoders.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/radeon/atombios_encoders.c b/drivers/gpu/drm/radeon/atombios_encoders.c
> index 4e984973c043..b62fd713efcf 100644
> --- a/drivers/gpu/drm/radeon/atombios_encoders.c
> +++ b/drivers/gpu/drm/radeon/atombios_encoders.c
> @@ -1383,7 +1383,7 @@ atombios_set_edp_panel_power(struct drm_connector *connector, int action)
>         if (connector->connector_type != DRM_MODE_CONNECTOR_eDP)
>                 goto done;
>
> -       if (!ASIC_IS_DCE4(rdev))
> +       if (!ASIC_IS_DCE31(rdev))
>                 goto done;
>
>         if ((action != ATOM_TRANSMITTER_ACTION_POWER_ON) &&
> @@ -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) || ASIC_IS_DCE31(rdev))
>                                 atombios_dig_encoder_setup(encoder, ATOM_ENCODER_CMD_DP_VIDEO_ON, 0);
>                 }
>                 if (radeon_encoder->devices & (ATOM_DEVICE_LCD_SUPPORT)) {
> @@ -1724,7 +1724,7 @@ radeon_atom_encoder_dpms_dig(struct drm_encoder *encoder, int mode)
>         case DRM_MODE_DPMS_SUSPEND:
>         case DRM_MODE_DPMS_OFF:
>
> -               if (ASIC_IS_DCE4(rdev)) {
> +               if (ASIC_IS_DCE4(rdev) || ASIC_IS_DCE31(rdev)) {
>                         if (ENCODER_MODE_IS_DP(atombios_get_encoder_mode(encoder)) && connector)
>                                 atombios_dig_encoder_setup(encoder, ATOM_ENCODER_CMD_DP_VIDEO_OFF, 0);
>                 }

These changes don't make sense and will break other DCE3.c boards.   I
had the attached patch from you in one of my old branches, does it fix
the issue?

Alex

[-- Attachment #2: 0001-drm-radeon-Fix-eDP-for-single-display-iMac11-1.patch --]
[-- Type: text/x-patch, Size: 3753 bytes --]

From ca4fc2fd58dcd3bf9f6afd8d37b27a1cfcc42337 Mon Sep 17 00:00:00 2001
From: Gilles Risch <gilles.risch@gmail.com>
Date: Fri, 17 Nov 2023 20:48:24 +0100
Subject: [PATCH] drm/radeon: Fix eDP for single-display iMac11,1

The Apple iMac11,1 (late 2009) has an integrated ATI Mobility Radeon HD 4850.
This machine suffers from a similar problem as the iMac10,1 (late 2009) and
the iMac11,2 (mid 2010). This small patch fixes the issue on this machine.

Fixes freedesktop issue 164
Link: https://gitlab.freedesktop.org/xorg/driver/xf86-video-ati/-/issues/164

Signed-off-by: Gilles Risch <gilles.risch@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
---
 drivers/gpu/drm/radeon/atombios_crtc.c     | 4 ++--
 drivers/gpu/drm/radeon/atombios_encoders.c | 9 +++++----
 drivers/gpu/drm/radeon/radeon.h            | 1 +
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index 2fc0334e0d6c5..3c6d332739e3c 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -580,7 +580,7 @@ static u32 atombios_adjust_pll(struct drm_crtc *crtc,
 			radeon_crtc->pll_flags |= (/*RADEON_PLL_USE_FRAC_FB_DIV |*/
 				RADEON_PLL_PREFER_CLOSEST_LOWER);
 
-		if (ASIC_IS_DCE32(rdev) && mode->clock > 200000)	/* range limits??? */
+		if (ASIC_IS_DCE31(rdev) && mode->clock > 200000)	/* range limits??? */
 			radeon_crtc->pll_flags |= RADEON_PLL_PREFER_HIGH_FB_DIV;
 		else
 			radeon_crtc->pll_flags |= RADEON_PLL_PREFER_LOW_REF_DIV;
@@ -594,7 +594,7 @@ 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_DCE31(rdev) && 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 3d9f47bc807af..37da7961ce792 100644
--- a/drivers/gpu/drm/radeon/atombios_encoders.c
+++ b/drivers/gpu/drm/radeon/atombios_encoders.c
@@ -2123,12 +2123,13 @@ 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.
+	 * On DCE31 and DCE32 any encoder can drive any block so usually just use crtc id,
+	 * but Apple thinks different at least on iMac10,1, iMac11,1 and iMac11,2,
+	 * so there use linkb, otherwise the internal eDP panel will stay dark.
 	 */
-	if (ASIC_IS_DCE32(rdev)) {
+	if (ASIC_IS_DCE31(rdev)) {
 		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;
 		else
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 527b9d19d7306..6b7c0abe49fb7 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -2625,6 +2625,7 @@ void r100_pll_errata_after_index(struct radeon_device *rdev);
 			    (rdev->family == CHIP_RS740)  ||	\
 			    (rdev->family >= CHIP_R600))
 #define ASIC_IS_DCE3(rdev) ((rdev->family >= CHIP_RV620))
+#define ASIC_IS_DCE31(rdev) ((rdev->family >= CHIP_RV770))
 #define ASIC_IS_DCE32(rdev) ((rdev->family >= CHIP_RV730))
 #define ASIC_IS_DCE4(rdev) ((rdev->family >= CHIP_CEDAR))
 #define ASIC_IS_DCE41(rdev) ((rdev->family >= CHIP_PALM) && \
-- 
2.54.0