On fi-cnl-y3 we have 2 modes that differ only by crtc_clock. This means
that if we request the normal mode, we automatically get the downclocked
mode.
This can be seen during boot:
[drm:drm_helper_probe_single_connector_modes] [CONNECTOR:101:eDP-1] probed modes :
[drm:drm_mode_debug_printmodeline] Modeline 102:"3840x2160" 60 533250 3840 3888 3920 4000 2160 2163 2168 2222 0x48 0xa
[drm:drm_mode_debug_printmodeline] Modeline 103:"3840x2160" 48 426600 3840 3888 3920 4000 2160 2163 2168 2222 0x40 0xa
...
[drm:intel_dump_pipe_config [i915]] [CRTC:51:pipe A][modeset]
[drm:intel_dump_pipe_config [i915]] output_types: EDP (0x100)
[drm:intel_dump_pipe_config [i915]] cpu_transcoder: EDP, pipe bpp: 24, dithering: 0
[drm:intel_dump_pipe_config [i915]] dp m_n: lanes: 4; gmch_m: 4970250, gmch_n: 8388608, link_m: 828375, link_n: 1048576, tu: 64
[drm:intel_dump_pipe_config [i915]] dp m2_n2: lanes: 4; gmch_m: 4970250, gmch_n: 8388608, link_m: 828375, link_n: 1048576, tu: 64
[drm:intel_dump_pipe_config [i915]] audio: 0, infoframes: 0
[drm:intel_dump_pipe_config [i915]] requested mode:
[drm:drm_mode_debug_printmodeline] Modeline 0:"3840x2160" 60 533250 3840 3888 3920 4000 2160 2163 2168 2222 0x48 0xa
[drm:intel_dump_pipe_config [i915]] adjusted mode:
[drm:drm_mode_debug_printmodeline] Modeline 0:"3840x2160" 48 426600 3840 3888 3920 4000 2160 2163 2168 2222 0x40 0xa
Testcase: kms_panel_fitting.atomic-fastset
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Fixes: dc911f5bd8aa ("drm/i915/edp: Allow alternate fixed mode for eDP if available.")
Cc: David Weinehall <david.weinehall@xxxxxxxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: Paulo Zanoni <paulo.r.zanoni@xxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Jim Bride <jim.bride@xxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v4.14+
---
drivers/gpu/drm/i915/intel_dp.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 9a4a51e79fa1..0bd3cc1c82b4 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1684,7 +1684,8 @@ static bool intel_edp_compare_alt_mode(struct drm_display_mode *m1,
m1->vdisplay == m2->vdisplay &&
m1->vsync_start == m2->vsync_start &&
m1->vsync_end == m2->vsync_end &&
- m1->vtotal == m2->vtotal);
+ m1->vtotal == m2->vtotal &&
+ m1->clock == m2->clock);
return bres;
}
--
2.16.2