From 755ee35fd1b5d5ae123a78a0ffb92f961fc32ba4 Mon Sep 17 00:00:00 2001
From: Liu Ying <victor.liu@nxp.com>
Date: Mon, 16 Aug 2021 16:33:23 +0800
Subject: [PATCH] LF-4321 drm/bridge: nwl-dsi: Avoid double modeset
When running the below system suspend/resume test case on
i.MX8ulp EVK platform with RM68200 MIPI DSI panel enabled,
panel register access would fail when the DRM connector's
DPMS property is changed from off to on after system resumes,
if the DPMS property is off before system suspends.
The root cause is that the bridge_funcs->mode_set() is called
twice during the procedure without bridge disablement, one at
system resume stage and one for DPMS on operation. That means
the MIPI DPHY is not powered down during the procedure and
initialized/powered on twice. As the PHY core driver takes
reference count for the power on operation, the second power
on operation doesn't take effect, hence the DPHY stays at
the initialization status. This patch introduces a flag to
indicate if the modeset is done or not to avoid the doulbe
modeset so that the DPHY will be active when the panel registers
are accessed.
while true; do modetest -M imx-dcnano -w 34:DPMS:3; done &
while true; do /unit_tests/SRTC/rtcwakeup.out -s 2 -m mem; done
Fixes: 120ffd6bbd1a ("MLK-25574-4 drm/bridge: nwl-dsi: Get MIPI DSI controller and PHY ready in ->mode_set()")
Cc: Sandor Yu <Sandor.yu@nxp.com>
Reported-by: Zhang Bo <bo.zhang@nxp.com>
Reviewed-by: Sandor Yu <Sandor.yu@nxp.com>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Acked-by: Jason Liu <jason.hui.liu@nxp.com>
---
drivers/gpu/drm/bridge/nwl-dsi.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c
index 4c4415cd8005d3..8d42d567152ca6 100644
--- a/drivers/gpu/drm/bridge/nwl-dsi.c
+++ b/drivers/gpu/drm/bridge/nwl-dsi.c
@@ -185,6 +185,7 @@ struct nwl_dsi {
struct list_head valid_modes;
u32 clk_drop_lvl;
bool use_dcss;
+ bool modeset_done;
};
static const struct regmap_config nwl_dsi_regmap_config = {
@@ -925,6 +926,8 @@ nwl_dsi_bridge_atomic_post_disable(struct drm_bridge *bridge,
clk_disable_unprepare(dsi->lcdif_clk);
pm_runtime_put(dsi->dev);
+
+ dsi->modeset_done = false;
}
static unsigned long nwl_dsi_get_bit_clock(struct nwl_dsi *dsi,
@@ -1269,6 +1272,9 @@ nwl_dsi_bridge_mode_set(struct drm_bridge *bridge,
struct mode_config *config;
int ret;
+ if (dsi->modeset_done)
+ return;
+
DRM_DEV_DEBUG_DRIVER(dsi->dev, "Setting mode:\n");
drm_mode_debug_printmodeline(adjusted_mode);
@@ -1346,6 +1352,8 @@ nwl_dsi_bridge_mode_set(struct drm_bridge *bridge,
DRM_DEV_ERROR(dev, "Failed to deassert DSI: %d\n", ret);
return;
}
+
+ dsi->modeset_done = true;
}
static void
--
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