[Intel-gfx] [PATCH] drm/i915: Reject 446-480MHz HDMI clock on GLK

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

The BXT/GLK DPLL can't generate certain frequencies. We already
reject the 233-240MHz range on both. But on GLK the DPLL max
frequency was bumped from 300MHz to 594MHz, so now we get to
also worry about the 446-480MHz range (double the original
problem range). Reject any frequency within the higher
problematic range as well.

Cc: stable at vger.kernel.org
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/3000
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_hdmi.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c
index 66e1ac3887c6..b593a71e6517 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -2218,7 +2218,11 @@ hdmi_port_clock_valid(struct intel_hdmi *hdmi,
 					  has_hdmi_sink))
 		return MODE_CLOCK_HIGH;
 
-	/* BXT DPLL can't generate 223-240 MHz */
+	/* GLK DPLL can't generate 446-480 MHz */
+	if (IS_GEMINILAKE(dev_priv) && clock > 446666 && clock < 480000)
+		return MODE_CLOCK_RANGE;
+
+	/* BXT/GLK DPLL can't generate 223-240 MHz */
 	if (IS_GEN9_LP(dev_priv) && clock > 223333 && clock < 240000)
 		return MODE_CLOCK_RANGE;
 
-- 
2.26.2