6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Imre Deak <imre.deak@xxxxxxxxx>
commit 166ce267ae3f96e439d8ccc838e8ec4d8b4dab73 upstream.
Fix the port width programming in the DDI_BUF_CTL register on MTLP+,
where this had an off-by-one error.
Cc: <stable@xxxxxxxxxxxxxxx> # v6.5+
Fixes: b66a8abaa48a ("drm/i915/display/mtl: Fill port width in DDI_BUF_/TRANS_DDI_FUNC_/PORT_BUF_CTL for HDMI")
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20250214142001.552916-3-imre.deak@xxxxxxxxx
(cherry picked from commit b2ecdabe46d23db275f94cd7c46ca414a144818b)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/display/intel_ddi.c | 2 +-
drivers/gpu/drm/i915/i915_reg.h | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -3363,7 +3363,7 @@ static void intel_enable_ddi_hdmi(struct
intel_de_rmw(dev_priv, XELPDP_PORT_BUF_CTL1(dev_priv, port),
XELPDP_PORT_WIDTH_MASK | XELPDP_PORT_REVERSAL, port_buf);
- buf_ctl |= DDI_PORT_WIDTH(lane_count);
+ buf_ctl |= DDI_PORT_WIDTH(crtc_state->lane_count);
if (DISPLAY_VER(dev_priv) >= 20)
buf_ctl |= XE2LPD_DDI_BUF_D2D_LINK_ENABLE;
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3869,7 +3869,7 @@ enum skl_power_gate {
#define DDI_BUF_IS_IDLE (1 << 7)
#define DDI_BUF_CTL_TC_PHY_OWNERSHIP REG_BIT(6)
#define DDI_A_4_LANES (1 << 4)
-#define DDI_PORT_WIDTH(width) (((width) - 1) << 1)
+#define DDI_PORT_WIDTH(width) (((width) == 3 ? 4 : ((width) - 1)) << 1)
#define DDI_PORT_WIDTH_MASK (7 << 1)
#define DDI_PORT_WIDTH_SHIFT 1
#define DDI_INIT_DISPLAY_DETECTED (1 << 0)
