From c034e8a46e4cb703018fe7e10fe5a3a974d6a7c3 Mon Sep 17 00:00:00 2001 From: Mitul Golani Date: Thu, 17 Sep 2026 13:13:22 +0530 Subject: drm/i915/vrr: Disable DC balance by default Disable VRR DC balance by default due to timing issues observed on some panel/TCON combinations. Keep the module parameter to enable DC balance during debugging and to isolate DC balance effects from underlying VRR/display timing issues. --v2: - Make enable_dc_balance a bool and keep it disabled by default; fix the parameter type/value mismatch and correct the description (Chaitanya Kumar Borah, Jani Nikula) - Explain in the commit message why the feature is gated and why a module parameter is used (Jani Nikula) --v3: - Commit message update (Jani Nikula) Fixes: 555819270707 ("drm/i915/vrr: Enable DC Balance") Cc: # v7.0+ Signed-off-by: Mitul Golani Reviewed-by: Ankit Nautiyal Signed-off-by: Ankit Nautiyal Link: https://patch.msgid.link/20260917074322.2606738-1-mitulkumar.ajitkumar.golani@intel.com (cherry picked from commit d1ef78f0581e856c4238c751e9ae2884ce58c275) Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/display/intel_display_params.c | 4 ++++ drivers/gpu/drm/i915/display/intel_display_params.h | 1 + drivers/gpu/drm/i915/display/intel_vrr.c | 4 +++- 3 files changed, 8 insertions(+), 1 deletion(-) (limited to 'drivers/gpu') diff --git a/drivers/gpu/drm/i915/display/intel_display_params.c b/drivers/gpu/drm/i915/display/intel_display_params.c index 2aed110c5..ca0ef466b 100644 --- a/drivers/gpu/drm/i915/display/intel_display_params.c +++ b/drivers/gpu/drm/i915/display/intel_display_params.c @@ -120,6 +120,10 @@ intel_display_param_named_unsafe(enable_psr, int, 0400, "(0=disabled, 1=enable up to PSR1, 2=enable up to PSR2) " "Default: -1 (use per-chip default)"); +intel_display_param_named_unsafe(enable_dc_balance, bool, 0400, + "Enable VRR DC balance (0=disabled, 1=enabled). " + "Default: 0 (disabled)"); + intel_display_param_named_unsafe(enable_panel_replay, int, 0400, "Enable Panel Replay (0=disabled, 1=enabled). Default: -1 (use per-chip default)"); diff --git a/drivers/gpu/drm/i915/display/intel_display_params.h b/drivers/gpu/drm/i915/display/intel_display_params.h index b95ecf728..16759e94c 100644 --- a/drivers/gpu/drm/i915/display/intel_display_params.h +++ b/drivers/gpu/drm/i915/display/intel_display_params.h @@ -46,6 +46,7 @@ struct drm_printer; param(bool, enable_dp_mst, true, 0600) \ param(int, enable_fbc, -1, 0600) \ param(int, enable_psr, -1, 0600) \ + param(bool, enable_dc_balance, false, 0600) \ param(int, enable_panel_replay, -1, 0600) \ param(bool, psr_safest_params, false, 0400) \ param(bool, enable_psr2_sel_fetch, true, 0400) \ diff --git a/drivers/gpu/drm/i915/display/intel_vrr.c b/drivers/gpu/drm/i915/display/intel_vrr.c index 51e4f3309..cfc0cfbff 100644 --- a/drivers/gpu/drm/i915/display/intel_vrr.c +++ b/drivers/gpu/drm/i915/display/intel_vrr.c @@ -386,10 +386,12 @@ static bool intel_vrr_dc_balance_possible(const struct intel_crtc_state *crtc_st static void intel_vrr_dc_balance_compute_config(struct intel_crtc_state *crtc_state) { + struct intel_display *display = to_intel_display(crtc_state); int guardband_usec, adjustment_usec; struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode; - if (!intel_vrr_dc_balance_possible(crtc_state) || !crtc_state->vrr.enable) + if (!intel_vrr_dc_balance_possible(crtc_state) || + !crtc_state->vrr.enable || !display->params.enable_dc_balance) return; crtc_state->vrr.dc_balance.vmax = crtc_state->vrr.vmax; -- cgit v1.3.1