From 93aa3eb06df79f0d9d66cf66c5ccdef933ca3374 Mon Sep 17 00:00:00 2001 From: Eric Anholt Date: Tue, 31 Oct 2017 12:32:57 -0700 Subject: [PATCH] drm/vc4: Skip ULPS latching when we're in that ULPS state already. 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 Link: https://patchwork.freedesktop.org/patch/msgid/20171031193258.17373-1-eric@anholt.net Reviewed-by: Boris Brezillon --- 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 94085f8bcd68c..8aa8978351185 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); -- 2.39.5