Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
drm/i915/alpm: Allow LOBF only if window1 > alpm check_entry lines
LOBF must be disabled if the number of lines within Window 1 is not greater
than ALPM_CTL[ALPM Entry Check]
v2: Consider the case where SCL is in the active region. (Ville)
Bspec:71041
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Michał Grzelak <michal.grzelak@intel.com>
Link: https://patch.msgid.link/20260204050250.762718-3-ankit.k.nautiyal@intel.com
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drivers/gpu/drm/i915/display/intel_alpm.c
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drivers/gpu/drm/i915/display/intel_alpm.c
···
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return first_sdp_position + waketime_in_lines + crtc_state->set_context_latency;
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}
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static bool intel_alpm_lobf_is_window1_sufficient(struct intel_crtc_state *crtc_state)
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{
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struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
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int vblank = adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vdisplay;
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int window1;
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/*
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* LOBF must be disabled if the number of lines within Window 1 is not
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* greater than ALPM_CTL[ALPM Entry Check]
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*/
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window1 = vblank - min(vblank,
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crtc_state->vrr.guardband +
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crtc_state->set_context_latency);
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return window1 > crtc_state->alpm_state.check_entry_lines;
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}
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void intel_alpm_lobf_compute_config_late(struct intel_dp *intel_dp,
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struct intel_crtc_state *crtc_state)
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{
···
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if (!crtc_state->has_lobf)
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return;
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if (!intel_alpm_lobf_is_window1_sufficient(crtc_state)) {
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crtc_state->has_lobf = false;
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return;
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}
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/*
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* LOBF can only be enabled if the time from the start of the SCL+Guardband