drm/i915/xe2lpd: implement WA for underruns while enabling FBC

FIFO underruns are observed when FBC is enabled on plane 2 or
plane 3. Recommended WA is to update the FBC enabling sequence.
The plane binding register bits need to be updated separately
before programming the FBC enable bit.

Bspec: 74151
Reviewed-by: Mika Kahola <[e-mail]> #v3
Signed-off-by: Vinod Govindapillai <[e-mail]>
Reviewed-by: Mika Kahola <[e-mail]>
Signed-off-by: Mika Kahola <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/i915/display/intel_fbc.c

···
 static void ivb_fbc_activate(struct intel_fbc *fbc)
 {
 	struct drm_i915_private *i915 = fbc->i915;
+	u32 dpfc_ctl;
 
 	if (DISPLAY_VER(i915) >= 10)
 		glk_fbc_program_cfb_stride(fbc);
···
 	if (intel_gt_support_legacy_fencing(to_gt(i915)))
 		snb_fbc_program_fence(fbc);
 
+	/* wa_14019417088 Alternative WA*/
+	dpfc_ctl = ivb_dpfc_ctl(fbc);
+	if (DISPLAY_VER(i915) >= 20)
+		intel_de_write(i915, ILK_DPFC_CONTROL(fbc->id), dpfc_ctl);
+
 	intel_de_write(i915, ILK_DPFC_CONTROL(fbc->id),
-		       DPFC_CTL_EN | ivb_dpfc_ctl(fbc));
+		       DPFC_CTL_EN | dpfc_ctl);
 }
 
 static bool ivb_fbc_is_compressing(struct intel_fbc *fbc)