drm/i915: Remove unused underrun irq/reporting bits

Underrun recovery was defeatured and was never brought into usage.
Thus we can remove the underrun recovery interrupt/reporting
register bits and related logic introduced to detect/report soft,
hard, port underruns.

Essentially this is a revert of the commit 8bcc0840cf7c
("drm/i915/xelpd: Enhanced pipe underrun reporting") which originally
added this functionality. Also note that PIPE_STATUS_UNDERRUN bit in
PIPESTATUS still stays relevant but we would move back to not
clearing this sticky bit as we are not using any information from
this register.

v2: Extend commit message to add more details (Matt Roper)
v3: Fix the old commit mention in commit message

Signed-off-by: Sai Teja Pottumuttu <sai.teja.pottumuttu@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241015080503.3521063-1-sai.teja.pottumuttu@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

1 files changed, 5 insertions, 53 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_fifo_underrun.c b/drivers/gpu/drm/i915/display/intel_fifo_underrun.c
index 745ce22afb89..cda1daf4cdea 100644
--- a/drivers/gpu/drm/i915/display/intel_fifo_underrun.c
+++ b/drivers/gpu/drm/i915/display/intel_fifo_underrun.c
@@ -192,35 +192,15 @@ static void ivb_set_fifo_underrun_reporting(struct drm_device *dev,
 	}
 }
 
-static u32
-icl_pipe_status_underrun_mask(struct drm_i915_private *dev_priv)
-{
-	u32 mask = PIPE_STATUS_UNDERRUN;
-
-	if (DISPLAY_VER(dev_priv) >= 13)
-		mask |= PIPE_STATUS_SOFT_UNDERRUN_XELPD |
-			PIPE_STATUS_HARD_UNDERRUN_XELPD |
-			PIPE_STATUS_PORT_UNDERRUN_XELPD;
-
-	return mask;
-}
-
 static void bdw_set_fifo_underrun_reporting(struct drm_device *dev,
 					    enum pipe pipe, bool enable)
 {
 	struct drm_i915_private *dev_priv = to_i915(dev);
-	u32 mask = gen8_de_pipe_underrun_mask(dev_priv);
-
-	if (enable) {
-		if (DISPLAY_VER(dev_priv) >= 11)
-			intel_de_write(dev_priv,
-				       ICL_PIPESTATUS(dev_priv, pipe),
-				       icl_pipe_status_underrun_mask(dev_priv));
 
-		bdw_enable_pipe_irq(dev_priv, pipe, mask);
-	} else {
-		bdw_disable_pipe_irq(dev_priv, pipe, mask);
-	}
+	if (enable)
+		bdw_enable_pipe_irq(dev_priv, pipe, GEN8_PIPE_FIFO_UNDERRUN);
+	else
+		bdw_disable_pipe_irq(dev_priv, pipe, GEN8_PIPE_FIFO_UNDERRUN);
 }
 
 static void ibx_set_fifo_underrun_reporting(struct drm_device *dev,
@@ -404,7 +384,6 @@ void intel_cpu_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv,
 {
 	struct intel_display *display = &dev_priv->display;
 	struct intel_crtc *crtc = intel_crtc_for_pipe(display, pipe);
-	u32 underruns = 0;
 
 	/* We may be called too early in init, thanks BIOS! */
 	if (crtc == NULL)
@@ -415,37 +394,10 @@ void intel_cpu_fifo_underrun_irq_handler(struct drm_i915_private *dev_priv,
 	    crtc->cpu_fifo_underrun_disabled)
 		return;
 
-	/*
-	 * Starting with display version 11, the PIPE_STAT register records
-	 * whether an underrun has happened, and on XELPD+, it will also record
-	 * whether the underrun was soft/hard and whether it was triggered by
-	 * the downstream port logic.  We should clear these bits (which use
-	 * write-1-to-clear logic) too.
-	 *
-	 * Note that although the IIR gives us the same underrun and soft/hard
-	 * information, PIPE_STAT is the only place we can find out whether
-	 * the underrun was caused by the downstream port.
-	 */
-	if (DISPLAY_VER(dev_priv) >= 11) {
-		underruns = intel_de_read(dev_priv,
-					  ICL_PIPESTATUS(dev_priv, pipe)) &
-			icl_pipe_status_underrun_mask(dev_priv);
-		intel_de_write(dev_priv, ICL_PIPESTATUS(dev_priv, pipe),
-			       underruns);
-	}
-
 	if (intel_set_cpu_fifo_underrun_reporting(dev_priv, pipe, false)) {
 		trace_intel_cpu_fifo_underrun(display, pipe);
 
-		if (DISPLAY_VER(dev_priv) >= 11)
-			drm_err(&dev_priv->drm, "CPU pipe %c FIFO underrun: %s%s%s%s\n",
-				pipe_name(pipe),
-				underruns & PIPE_STATUS_SOFT_UNDERRUN_XELPD ? "soft," : "",
-				underruns & PIPE_STATUS_HARD_UNDERRUN_XELPD ? "hard," : "",
-				underruns & PIPE_STATUS_PORT_UNDERRUN_XELPD ? "port," : "",
-				underruns & PIPE_STATUS_UNDERRUN ? "transcoder," : "");
-		else
-			drm_err(&dev_priv->drm, "CPU pipe %c FIFO underrun\n", pipe_name(pipe));
+		drm_err(&dev_priv->drm, "CPU pipe %c FIFO underrun\n", pipe_name(pipe));
 	}
 
 	intel_fbc_handle_fifo_underrun_irq(&dev_priv->display);