From 0f8839f5f323da04a800e6ced1136e4b1e1689a9 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Thu, 13 Feb 2020 16:04:12 +0200 Subject: [PATCH] drm/i915: Force state->modeset=true when distrust_bios_wm==true MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Currently when we load the driver we set distrust_bios_wm=true, which will cause active_pipe_changes to get flagged even when we're not toggling any pipes on/off. The reason being that we want to fully redistribute the dbuf among the active pipes and ignore whatever state the firmware left behind. Unfortunately when the code flags active_pipe_changes it doesn't set state->modeset to true, which means the hardware dbuf state won't actually get updated. Hence the hardware and software states go out of sync, which can result in planes trying to use a disabled dbuf slice. Suprisingly that only seems to corrupt the display rather than making the whole display engine keel over. Let's fix this for now by flagging state->modeset whenever distrust_bios_wm is set. Eventually we'll likely want to rip out all of this mess and introduce proper statye tracking for dbuf. But that requires more work. Toss in a FIXME to that effect. Cc: Stanislav Lisovskiy Fixes: ff2cd8635e41 ("drm/i915: Correctly map DBUF slices to pipes") Signed-off-by: Ville Syrjälä Reviewed-by: Stanislav Lisovskiy Reviewed-by: Matt Roper Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20200213140412.32697-4-stanislav.lisovskiy@intel.com --- drivers/gpu/drm/i915/display/intel_display.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index 1e3f2cc..df47b2f 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -15027,6 +15027,20 @@ static int intel_atomic_check(struct drm_device *dev, if (new_cdclk_state && new_cdclk_state->force_min_cdclk_changed) any_ms = true; + /* + * distrust_bios_wm will force a full dbuf recomputation + * but the hardware state will only get updated accordingly + * if state->modeset==true. Hence distrust_bios_wm==true && + * state->modeset==false is an invalid combination which + * would cause the hardware and software dbuf state to get + * out of sync. We must prevent that. + * + * FIXME clean up this mess and introduce better + * state tracking for dbuf. + */ + if (dev_priv->wm.distrust_bios_wm) + any_ms = true; + if (any_ms) { ret = intel_modeset_checks(state); if (ret) -- 2.7.4