Re: [PATCH v6] drm/radeon: fix internal display on iMac11, 1 (RV770/DCE3.1)

Applied.  Thanks!

Alex

On Sun, Aug 16, 2026 at 8:43 PM Gilles Risch <[email protected]> wrote:
>
> 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 <[email protected]>
>
> Good morning,
>
> this is v6 of the patch, rebased on top of amd-staging-drm-next
> (agd5f/linux).
>
> There are no functional or code changes since v5.
>
> Regarding Lukas Wunner's previous Reviewed-by (which was provided on v2),
> I have kept him in CC so he can confirm if his review still stands given
> the changes between v2 and v5.
>
> Could you have a look at this when you have a spare moment?
>
> Regards,
> Gilles
>
> Changes in v6:
> - Rebased on amd-staging-drm-next (no functional/code changes since v5)
> ---
>  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 2fc0334e0d6c..075eba2d47f3 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 5cfd8fcfa5e8..8b3f8303a967 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;
>         }
>
>
> base-commit: 21c50d41af7c46e138b542dba2dcf6d2a978ae99
> --
> 2.47.3
>