[PATCH 5.3 066/193] intel_th: gth: Fix the window switching sequence

[Greg Kroah-Hartman]

From: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>

commit 87c0b9c79ec136ea76a14a88d675a746bc6a87f9 upstream.

Commit 8116db57cf16 ("intel_th: Add switch triggering support") added
a trigger assertion of the CTS, but forgot to de-assert it at the end
of the sequence. This results in window switches randomly not happening.

Fix that by de-asserting the trigger at the end of the window switch
sequence.

Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Fixes: 8116db57cf16 ("intel_th: Add switch triggering support")
Cc: stable <stable@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20191028070651.9770-2-alexander.shishkin@xxxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/hwtracing/intel_th/gth.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/hwtracing/intel_th/gth.c
+++ b/drivers/hwtracing/intel_th/gth.c
@@ -626,6 +626,9 @@ static void intel_th_gth_switch(struct i
 	if (!count)
 		dev_dbg(&thdev->dev, "timeout waiting for CTS Trigger\n");
 
+	/* De-assert the trigger */
+	iowrite32(0, gth->base + REG_CTS_CTL);
+
 	intel_th_gth_stop(gth, output, false);
 	intel_th_gth_start(gth, output);
 }