From f5b8c316092f2501ca32ac32f5c6303e2c58ef50 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Wed, 29 Sep 2021 21:45:36 +0300 Subject: [PATCH] drm/i915: Reject user modes that don't match fixed mode's refresh rate MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit When using a panel with a fixed mode we don't change the refresh rate of the display. Reject any user requested mode which doesn't match that fixed refresh rate. Unfortunately when Xorg sees the scaling_mode property on the connecor it likes to automagically cook up modes whose refresh rate is a fair bit off from the fixed refresh rate we use. So we have to give it some extra latitude so that we don't start to reject all of it. v2: sDVO now uses intel_panel_compute_config() too v3: Add a debug message to inform the user what happened References: https://gitlab.freedesktop.org/drm/intel/-/issues/2939 References: https://gitlab.freedesktop.org/drm/intel/-/issues/3969 Signed-off-by: Ville Syrjälä Reviewed-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20210929184536.8332-1-ville.syrjala@linux.intel.com --- drivers/gpu/drm/i915/display/intel_panel.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c index 77c1ca387de0..a0c8e43db5eb 100644 --- a/drivers/gpu/drm/i915/display/intel_panel.c +++ b/drivers/gpu/drm/i915/display/intel_panel.c @@ -53,6 +53,21 @@ int intel_panel_compute_config(struct intel_connector *connector, if (!fixed_mode) return 0; + /* + * We don't want to lie too much to the user about the refresh + * rate they're going to get. But we have to allow a bit of latitude + * for Xorg since it likes to automagically cook up modes with slightly + * off refresh rates. + */ + if (abs(drm_mode_vrefresh(adjusted_mode) - drm_mode_vrefresh(fixed_mode)) > 1) { + drm_dbg_kms(connector->base.dev, + "[CONNECTOR:%d:%s] Requested mode vrefresh (%d Hz) does not match fixed mode vrefresh (%d Hz)\n", + connector->base.base.id, connector->base.name, + drm_mode_vrefresh(adjusted_mode), drm_mode_vrefresh(fixed_mode)); + + return -EINVAL; + } + drm_mode_copy(adjusted_mode, fixed_mode); drm_mode_set_crtcinfo(adjusted_mode, 0); -- 2.11.0