Re: [PATCH] drm/radeon: fix eDP resume from suspend on iMac11, 1 / DCE3.1 systems
On Mon, May 18, 2026 at 10:40 AM Gilles Risch wrote:
>
> Am Mo., 18. Mai 2026 um 16:13 Uhr schrieb Alex Deucher
> :
> >
> > On Sat, May 16, 2026 at 2:52 PM Gilles Risch 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
> > > ---
> > > 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
>
> While the initial attached patch resolved the dark screen issue after
> a fresh boot, this follow-up patch addresses the same problem
> occurring after resuming from suspend. Should I used dmi_match() to
> avoid breaking other DCE3.c boards?
Yes. Even that is a hack. You are effectively just skipping some of
the required programming sequences. Presumably the mac is wired up
strangely or there are issues with its atom tables. Ideally we'd sort
that out, but this hardware is pretty old so I'm ok with a hack.
Alex
Re: [PATCH] drm/radeon: fix eDP resume from suspend on iMac11, 1 / DCE3.1 systems
Am Mo., 18. Mai 2026 um 16:13 Uhr schrieb Alex Deucher :
>
> On Sat, May 16, 2026 at 2:52 PM Gilles Risch 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
> > ---
> > 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
While the initial attached patch resolved the dark screen issue after
a fresh boot, this follow-up patch addresses the same problem
occurring after resuming from suspend. Should I used dmi_match() to
avoid breaking other DCE3.c boards?
Regards,
Gilles
Re: [PATCH] drm/radeon: fix eDP resume from suspend on iMac11, 1 / DCE3.1 systems
On Sat, May 16, 2026 at 2:52 PM Gilles Risch 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
> ---
> 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
From ca4fc2fd58dcd3bf9f6afd8d37b27a1cfcc42337 Mon Sep 17 00:00:00 2001
From: Gilles Risch
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
Signed-off-by: Alex Deucher
---
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 > 20) /* range limits??? */
+ if (ASIC_IS_DCE31(rdev) && mode->clock > 20) /* 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_encod
Re: [PATCH] drm/radeon: fix eDP resume from suspend on iMac11, 1 / DCE3.1 systems
Hi Gilles, kernel test robot noticed the following build errors: [auto build test ERROR on drm-misc/drm-misc-next] [also build test ERROR on linus/master v7.1-rc3 next-20260508] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Gilles-Risch/drm-radeon-fix-eDP-resume-from-suspend-on-iMac11-1-DCE3-1-systems/20260517-025343 base: https://gitlab.freedesktop.org/drm/misc/kernel.git drm-misc-next patch link: https://lore.kernel.org/r/20260516185226.3005-1-gilles.risch%40gmail.com patch subject: [PATCH] drm/radeon: fix eDP resume from suspend on iMac11, 1 / DCE3.1 systems config: riscv-randconfig-002-20260517 (https://download.01.org/0day-ci/archive/20260517/[email protected]/config) compiler: riscv32-linux-gcc (GCC) 15.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260517/[email protected]/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/ All errors (new ones prefixed by >>): drivers/gpu/drm/radeon/atombios_encoders.c: In function 'atombios_set_edp_panel_power': >> drivers/gpu/drm/radeon/atombios_encoders.c:1386:14: error: implicit >> declaration of function 'ASIC_IS_DCE31'; did you mean 'ASIC_IS_DCE3'? >> [-Wimplicit-function-declaration] 1386 | if (!ASIC_IS_DCE31(rdev)) | ^ | ASIC_IS_DCE3 vim +1386 drivers/gpu/drm/radeon/atombios_encoders.c 1372 1373 bool 1374 atombios_set_edp_panel_power(struct drm_connector *connector, int action) 1375 { 1376 struct radeon_connector *radeon_connector = to_radeon_connector(connector); 1377 struct drm_device *dev = radeon_connector->base.dev; 1378 struct radeon_device *rdev = dev->dev_private; 1379 union dig_transmitter_control args; 1380 int index = GetIndexIntoMasterTable(COMMAND, UNIPHYTransmitterControl); 1381 uint8_t frev, crev; 1382 1383 if (connector->connector_type != DRM_MODE_CONNECTOR_eDP) 1384 goto done; 1385 > 1386 if (!ASIC_IS_DCE31(rdev)) 1387 goto done; 1388 1389 if ((action != ATOM_TRANSMITTER_ACTION_POWER_ON) && 1390 (action != ATOM_TRANSMITTER_ACTION_POWER_OFF)) 1391 goto done; 1392 1393 if (!atom_parse_cmd_header(rdev->mode_info.atom_context, index, &frev, &crev)) 1394 goto done; 1395 1396 memset(&args, 0, sizeof(args)); 1397 1398 args.v1.ucAction = action; 1399 1400 atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args, sizeof(args)); 1401 1402 /* wait for the panel to power up */ 1403 if (action == ATOM_TRANSMITTER_ACTION_POWER_ON) { 1404 int i; 1405 1406 for (i = 0; i < 300; i++) { 1407 if (radeon_hpd_sense(rdev, radeon_connector->hpd.hpd)) 1408 return true; 1409 mdelay(1); 1410 } 1411 return false; 1412 } 1413 done: 1414 return true; 1415 } 1416 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
Re: [PATCH] drm/radeon: fix eDP resume from suspend on iMac11, 1 / DCE3.1 systems
Hi Gilles, kernel test robot noticed the following build errors: [auto build test ERROR on drm-misc/drm-misc-next] [also build test ERROR on linus/master v7.1-rc3 next-20260508] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Gilles-Risch/drm-radeon-fix-eDP-resume-from-suspend-on-iMac11-1-DCE3-1-systems/20260517-025343 base: https://gitlab.freedesktop.org/drm/misc/kernel.git drm-misc-next patch link: https://lore.kernel.org/r/20260516185226.3005-1-gilles.risch%40gmail.com patch subject: [PATCH] drm/radeon: fix eDP resume from suspend on iMac11, 1 / DCE3.1 systems config: riscv-randconfig-001-20260517 (https://download.01.org/0day-ci/archive/20260517/[email protected]/config) compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project 5bac06718f502014fade905512f1d26d578a18f3) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260517/[email protected]/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/ All errors (new ones prefixed by >>): >> drivers/gpu/drm/radeon/atombios_encoders.c:1386:7: error: call to undeclared >> function 'ASIC_IS_DCE31'; ISO C99 and later do not support implicit function >> declarations [-Wimplicit-function-declaration] 1386 | if (!ASIC_IS_DCE31(rdev)) | ^ drivers/gpu/drm/radeon/atombios_encoders.c:1710:30: error: call to undeclared function 'ASIC_IS_DCE31'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 1710 | if (ASIC_IS_DCE4(rdev) || ASIC_IS_DCE31(rdev)) | ^ drivers/gpu/drm/radeon/atombios_encoders.c:1727:29: error: call to undeclared function 'ASIC_IS_DCE31'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 1727 | if (ASIC_IS_DCE4(rdev) || ASIC_IS_DCE31(rdev)) { | ^ 3 errors generated. vim +/ASIC_IS_DCE31 +1386 drivers/gpu/drm/radeon/atombios_encoders.c 1372 1373 bool 1374 atombios_set_edp_panel_power(struct drm_connector *connector, int action) 1375 { 1376 struct radeon_connector *radeon_connector = to_radeon_connector(connector); 1377 struct drm_device *dev = radeon_connector->base.dev; 1378 struct radeon_device *rdev = dev->dev_private; 1379 union dig_transmitter_control args; 1380 int index = GetIndexIntoMasterTable(COMMAND, UNIPHYTransmitterControl); 1381 uint8_t frev, crev; 1382 1383 if (connector->connector_type != DRM_MODE_CONNECTOR_eDP) 1384 goto done; 1385 > 1386 if (!ASIC_IS_DCE31(rdev)) 1387 goto done; 1388 1389 if ((action != ATOM_TRANSMITTER_ACTION_POWER_ON) && 1390 (action != ATOM_TRANSMITTER_ACTION_POWER_OFF)) 1391 goto done; 1392 1393 if (!atom_parse_cmd_header(rdev->mode_info.atom_context, index, &frev, &crev)) 1394 goto done; 1395 1396 memset(&args, 0, sizeof(args)); 1397 1398 args.v1.ucAction = action; 1399 1400 atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args, sizeof(args)); 1401 1402 /* wait for the panel to power up */ 1403 if (action == ATOM_TRANSMITTER_ACTION_POWER_ON) { 1404 int i; 1405 1406 for (i = 0; i < 300; i++) { 1407 if (radeon_hpd_sense(rdev, radeon_connector->hpd.hpd)) 1408 return true; 1409 mdelay(1); 1410 } 1411 return false; 1412 } 1413 done: 1414 return true; 1415 } 1416 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
