[PATCH 13/18] drm/i915/vblank: use generic read_poll_timeout() instead of wait_for()

[Jani Nikula]

Prefer generic poll helpers over i915 custom helpers.

The functional change is losing the exponentially growing sleep of
wait_for(), which used to be 10, 20, 40, ..., 640, and 1280 us.

Use an arbitrary constant 500 us sleep instead. The timeout remains at
100 ms.

Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/display/intel_vblank.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_vblank.c b/drivers/gpu/drm/i915/display/intel_vblank.c
index 70ba7aa26bf4..98ab7f03ec8d 100644
--- a/drivers/gpu/drm/i915/display/intel_vblank.c
+++ b/drivers/gpu/drm/i915/display/intel_vblank.c
@@ -3,6 +3,8 @@
  * Copyright © 2022-2023 Intel Corporation
  */
 
+#include <linux/iopoll.h>
+
 #include <drm/drm_vblank.h>
 
 #include "i915_drv.h"
@@ -492,9 +494,15 @@ static void wait_for_pipe_scanline_moving(struct intel_crtc *crtc, bool state)
 {
 	struct intel_display *display = to_intel_display(crtc);
 	enum pipe pipe = crtc->pipe;
+	bool is_moving;
+	int ret;
 
 	/* Wait for the display line to settle/start moving */
-	if (wait_for(pipe_scanline_is_moving(display, pipe) == state, 100))
+	ret = read_poll_timeout(pipe_scanline_is_moving, is_moving,
+				is_moving == state,
+				500, 100 * 1000, false,
+				display, pipe);
+	if (ret)
 		drm_err(display->drm,
 			"pipe %c scanline %s wait timed out\n",
 			pipe_name(pipe), str_on_off(state));
-- 
2.39.5