[PATCH 4/6] drm/i915/vga: Include the current pipe in the VGA disable debug message

[Ville Syrjala]

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

Add some debugs to the VGA plane disable so that we can at least
see from the logs when it happens (and on which pipe). I was curious
about this at some point when I was seeing some random underruns
near the time when we disable the VGA plane, but I think in the end
that turned out to be a red herring.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_vga.c | 29 +++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_vga.c b/drivers/gpu/drm/i915/display/intel_vga.c
index 56047f701798..7ee689a9da92 100644
--- a/drivers/gpu/drm/i915/display/intel_vga.c
+++ b/drivers/gpu/drm/i915/display/intel_vga.c
@@ -12,6 +12,7 @@
 #include "i915_drv.h"
 #include "i915_reg.h"
 #include "intel_de.h"
+#include "intel_display.h"
 #include "intel_vga.h"
 #include "intel_vga_regs.h"
 
@@ -25,16 +26,42 @@ static i915_reg_t intel_vga_cntrl_reg(struct intel_display *display)
 		return VGACNTRL;
 }
 
+static bool has_vga_pipe_sel(struct intel_display *display)
+{
+	if (display->platform.i845g ||
+	    display->platform.i865g)
+		return false;
+
+	if (display->platform.valleyview ||
+	    display->platform.cherryview)
+		return true;
+
+	return DISPLAY_VER(display) < 7;
+}
+
 /* Disable the VGA plane that we never use */
 void intel_vga_disable(struct intel_display *display)
 {
 	struct pci_dev *pdev = to_pci_dev(display->drm->dev);
 	i915_reg_t vga_reg = intel_vga_cntrl_reg(display);
+	enum pipe pipe;
+	u32 tmp;
 	u8 sr1;
 
-	if (intel_de_read(display, vga_reg) & VGA_DISP_DISABLE)
+	tmp = intel_de_read(display, vga_reg);
+	if (tmp & VGA_DISP_DISABLE)
 		return;
 
+	if (display->platform.cherryview)
+		pipe = REG_FIELD_GET(VGA_PIPE_SEL_MASK_CHV, tmp);
+	else if (has_vga_pipe_sel(display))
+		pipe = REG_FIELD_GET(VGA_PIPE_SEL_MASK, tmp);
+	else
+		pipe = PIPE_A;
+
+	drm_dbg_kms(display->drm, "Disabling VGA plane on pipe %c\n",
+		    pipe_name(pipe));
+
 	/* WaEnableVGAAccessThroughIOPort:ctg,elk,ilk,snb,ivb,vlv,hsw */
 	vga_get_uninterruptible(pdev, VGA_RSRC_LEGACY_IO);
 	outb(0x01, VGA_SEQ_I);
-- 
2.49.0