[Intel-gfx] [PATCH] drm/i915/dp: Fix intel_edp_compare_alt_mode.

[Maarten Lankhorst]

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 at linux.intel.com>
Fixes: dc911f5bd8aa ("drm/i915/edp: Allow alternate fixed mode for eDP if available.")
Cc: David Weinehall <david.weinehall at linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
Cc: Jani Nikula <jani.nikula at intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Jim Bride <jim.bride at linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
Cc: <stable at vger.kernel.org> # 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