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* [PATCH 1/2] drm/vc4: Skip ULPS latching when we're in that ULPS state already.
@ 2017-10-31 19:32 Eric Anholt
  2017-10-31 19:32   ` Eric Anholt
  2018-04-30  9:03   ` Boris Brezillon
  0 siblings, 2 replies; 11+ messages in thread
From: Eric Anholt @ 2017-10-31 19:32 UTC (permalink / raw)
  To: dri-devel, Thierry Reding; +Cc: linux-kernel, Eric Anholt

It seems that trying to go from unlatched to unlatched will time out
waiting for STOP, and we can just skip that.

Signed-off-by: Eric Anholt <eric@anholt.net>
---
 drivers/gpu/drm/vc4/vc4_dsi.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_dsi.c b/drivers/gpu/drm/vc4/vc4_dsi.c
index 94085f8bcd68..8aa897835118 100644
--- a/drivers/gpu/drm/vc4/vc4_dsi.c
+++ b/drivers/gpu/drm/vc4/vc4_dsi.c
@@ -753,6 +753,11 @@ static void vc4_dsi_ulps(struct vc4_dsi *dsi, bool ulps)
 			 (dsi->lanes > 2 ? DSI1_STAT_PHY_D2_STOP : 0) |
 			 (dsi->lanes > 3 ? DSI1_STAT_PHY_D3_STOP : 0));
 	int ret;
+	bool ulps_currently_enabled = (DSI_PORT_READ(PHY_AFEC0) &
+				       DSI_PORT_BIT(PHY_AFEC0_LATCH_ULPS));
+
+	if (ulps == ulps_currently_enabled)
+		return;
 
 	DSI_PORT_WRITE(STAT, stat_ulps);
 	DSI_PORT_WRITE(PHYC, DSI_PORT_READ(PHYC) | phyc_ulps);
-- 
2.15.0

^ permalink raw reply related	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2018-04-30 21:04 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-10-31 19:32 [PATCH 1/2] drm/vc4: Skip ULPS latching when we're in that ULPS state already Eric Anholt
2017-10-31 19:32 ` [PATCH 2/2] drm/panel: Enable DSI transactions on the RPi panel Eric Anholt
2017-10-31 19:32   ` Eric Anholt
2018-04-30  9:04   ` Boris Brezillon
2018-04-30  9:04     ` Boris Brezillon
2018-04-30  9:27   ` Thierry Reding
2018-04-30  9:27     ` Thierry Reding
2018-04-30 21:04     ` Eric Anholt
2018-04-30 21:04       ` Eric Anholt
2018-04-30  9:03 ` [PATCH 1/2] drm/vc4: Skip ULPS latching when we're in that ULPS state already Boris Brezillon
2018-04-30  9:03   ` Boris Brezillon

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