Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
drm/i915: Simplify scanline_offset handling for gen2
Currently intel_crtc_scanline_offset() is careful to always
return a positive offset. That is not actually necessary
as long as we take care of negative values when applying the
offset in __intel_get_crtc_scanline().
This simplifies intel_crtc_scanline_offset(), and makes
the scanline_offfset arithmetic more symmetric between
the forward (__intel_get_crtc_scanline()) and reverse
(intel_crtc_scanline_to_hw()) directions.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240528185647.7765-5-ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
+3
-5
+3
-5
drivers/gpu/drm/i915/display/intel_vblank.c
+3
-5
drivers/gpu/drm/i915/display/intel_vblank.c
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* See update_scanline_offset() for the details on the
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* scanline_offset adjustment.
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*/
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-
return (position + crtc->scanline_offset) % vtotal;
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+
return (position + vtotal + crtc->scanline_offset) % vtotal;
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}
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int intel_crtc_scanline_to_hw(struct intel_crtc *crtc, int scanline)
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static int intel_crtc_scanline_offset(const struct intel_crtc_state *crtc_state)
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{
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struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
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-
const struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
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/*
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* The scanline counter increments at the leading edge of hsync.
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* last active line), the scanline counter will read vblank_start-1.
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*
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* On gen2 the scanline counter starts counting from 1 instead
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* of vtotal-1, so we have to subtract one (or rather add vtotal-1
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* to keep the value positive), instead of adding one.
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* of vtotal-1, so we have to subtract one.
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*
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* On HSW+ the behaviour of the scanline counter depends on the output
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* type. For DP ports it behaves like most other platforms, but on HDMI
···
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* answer that's slightly in the future.
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*/
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if (DISPLAY_VER(i915) == 2)
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return intel_mode_vtotal(adjusted_mode) - 1;
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return -1;
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else if (HAS_DDI(i915) && intel_crtc_has_type(crtc_state, INTEL_OUTPUT_HDMI))
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return 2;
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else