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

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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.

Reviewed-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Gilles Risch <gilles.risch@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

...

This commit is contained in:

Gilles Risch 2026-08-17 02:43:26 +02:00 • committed by Alex Deucher

parent 5c082f4cd1

commit 275c333258

2 changed files with 17 additions and 11 deletions

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5

drivers/gpu/drm/radeon/atombios_crtc.c

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23

drivers/gpu/drm/radeon/atombios_encoders.c

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