[Intel-gfx] [PATCH v2] drm/i915/display: Dual refresh rate fastset fixes with VRR fastset

[Manasi Navare]

Dual refresh rate (DRR) fastset seamlessly lets refresh rate
throttle without needing a full modeset.
However with the recent VRR fastset patches that got merged this
logic was broken. This is broken because now with VRR fastset
VRR parameters are calculated by default at the nominal refresh rate say 120Hz.
Now when DRR throttle happens to switch refresh rate to 60Hz, crtc clock
changes and this throws a mismatch in VRR parameters and fastset logic
for DRR gets thrown off and full modeset is indicated.

This patch fixes this by ignoring the pipe mismatch for VRR parameters
in the case of DRR and when VRR is not enabled. With this fix, DRR
will still throttle seamlessly as long as VRR is not enabled.

This will still need a full modeset for both DRR and VRR operating together
during the refresh rate throttle and then enabling VRR since now VRR
parameters need to be recomputed with new crtc clock and written to HW.

This DRR + VRR fastset in conjunction needs more work in the driver and
will be fixed in later patches.

v2:
Check for pipe config mismatch in crtc clock whenever VRR is enabled

Cc: Drew Davenport <ddavenport at chromium.org>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Sean Paul <seanpaul at chromium.org>
Signed-off-by: Manasi Navare <navaremanasi at chromium.org>
---
 drivers/gpu/drm/i915/display/intel_display.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 763ab569d8f3..efc407e11d8e 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -5352,7 +5352,7 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
 	if (IS_G4X(dev_priv) || DISPLAY_VER(dev_priv) >= 5)
 		PIPE_CONF_CHECK_I(pipe_bpp);
 
-	if (!fastset || !pipe_config->seamless_m_n) {
+	if (!fastset || !pipe_config->seamless_m_n || pipe_config->vrr.enable) {
 		PIPE_CONF_CHECK_I(hw.pipe_mode.crtc_clock);
 		PIPE_CONF_CHECK_I(hw.adjusted_mode.crtc_clock);
 	}
@@ -5387,11 +5387,13 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
 
 	if (!fastset)
 		PIPE_CONF_CHECK_BOOL(vrr.enable);
-	PIPE_CONF_CHECK_I(vrr.vmin);
-	PIPE_CONF_CHECK_I(vrr.vmax);
-	PIPE_CONF_CHECK_I(vrr.flipline);
-	PIPE_CONF_CHECK_I(vrr.pipeline_full);
-	PIPE_CONF_CHECK_I(vrr.guardband);
+	if ((!fastset && !pipe_config->seamless_m_n) || pipe_config->vrr.enable) {
+		PIPE_CONF_CHECK_I(vrr.vmin);
+		PIPE_CONF_CHECK_I(vrr.vmax);
+		PIPE_CONF_CHECK_I(vrr.flipline);
+		PIPE_CONF_CHECK_I(vrr.pipeline_full);
+		PIPE_CONF_CHECK_I(vrr.guardband);
+	}
 
 #undef PIPE_CONF_CHECK_X
 #undef PIPE_CONF_CHECK_I
-- 
2.41.0.640.ga95def55d0-goog