[PATCH 17/18] drm/i915/opregion: 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 1 ms sleep instead. The timeout remains, being
opregion defined, 50 ms by default, and 1500 ms at most.

Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/display/intel_opregion.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_opregion.c b/drivers/gpu/drm/i915/display/intel_opregion.c
index 2b8538fcfd1d..0c3f190c4bfa 100644
--- a/drivers/gpu/drm/i915/display/intel_opregion.c
+++ b/drivers/gpu/drm/i915/display/intel_opregion.c
@@ -28,6 +28,7 @@
 #include <linux/acpi.h>
 #include <linux/debugfs.h>
 #include <linux/dmi.h>
+#include <linux/iopoll.h>
 #include <acpi/video.h>
 
 #include <drm/drm_edid.h>
@@ -355,10 +356,14 @@ static int swsci(struct intel_display *display,
 	pci_write_config_word(pdev, SWSCI, swsci_val);
 
 	/* Poll for the result. */
-#define C (((scic = swsci->scic) & SWSCI_SCIC_INDICATOR) == 0)
-	if (wait_for(C, dslp)) {
+#define C(__swsci) ((__swsci)->scic)
+	ret = read_poll_timeout(C, scic,
+				(scic & SWSCI_SCIC_INDICATOR) == 0,
+				1000, dslp * 1000, false,
+				swsci);
+	if (ret) {
 		drm_dbg(display->drm, "SWSCI request timed out\n");
-		return -ETIMEDOUT;
+		return ret;
 	}
 
 	scic = (scic & SWSCI_SCIC_EXIT_STATUS_MASK) >>
-- 
2.39.5