diff mbox series

[v3] drm/msm/dp: do not complete dp_aux_cmd_fifo_tx() if irq is not for aux transfer

Message ID 1671137437-19587-1-git-send-email-quic_khsieh@quicinc.com (mailing list archive)
State New, archived
Headers show
Series [v3] drm/msm/dp: do not complete dp_aux_cmd_fifo_tx() if irq is not for aux transfer | expand

Commit Message

Kuogee Hsieh Dec. 15, 2022, 8:50 p.m. UTC 
There are 3 possible interrupt sources are handled by DP controller,
HPDstatus, Controller state changes and Aux read/write transaction.
At every irq, DP controller have to check isr status of every interrupt
sources and service the interrupt if its isr status bits shows interrupts
are pending. There is potential race condition may happen at current aux
isr handler implementation since it is always complete dp_aux_cmd_fifo_tx()
even irq is not for aux read or write transaction. This may cause aux read
transaction return premature if host aux data read is in the middle of
waiting for sink to complete transferring data to host while irq happen.
This will cause host's receiving buffer contains unexpected data. This
patch fixes this problem by checking aux isr and return immediately at
aux isr handler if there are no any isr status bits set.

Current there is a bug report regrading eDP edid corruption happen during
system booting up. After lengthy debugging to found that VIDEO_READY
interrupt was continuously firing during system booting up which cause
dp_aux_isr() to complete dp_aux_cmd_fifo_tx() prematurely to retrieve data
from aux hardware buffer which is not yet contains complete data transfer
from sink. This cause edid corruption.

Follows are the signature at kernel logs when problem happen,
EDID has corrupt header
panel-simple-dp-aux aux-aea0000.edp: Couldn't identify panel via EDID
panel-simple-dp-aux aux-aea0000.edp: error -EIO: Couldn't detect panel nor find a fallback

Changes in v2:
-- do complete if (ret == IRQ_HANDLED) ay dp-aux_isr()
-- add more commit text

Changes in v3:
-- add Stephen suggested
-- dp_aux_isr() return IRQ_XXX back to caller
-- dp_ctrl_isr() return IRQ_XXX back to caller

Fixes: c943b4948b58 ("drm/msm/dp: add displayPort driver support")

Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Tested-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Suggested-by: Stephen Boyd <swboyd@chromium.org>
---
 drivers/gpu/drm/msm/dp/dp_aux.c     | 95 ++++++++++++++++++++++++++-----------
 drivers/gpu/drm/msm/dp/dp_aux.h     |  2 +-
 drivers/gpu/drm/msm/dp/dp_ctrl.c    | 13 +++--
 drivers/gpu/drm/msm/dp/dp_ctrl.h    |  2 +-
 drivers/gpu/drm/msm/dp/dp_display.c | 16 +++++--
 5 files changed, 90 insertions(+), 38 deletions(-)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c
index d030a93..efb0f6c 100644
--- a/drivers/gpu/drm/msm/dp/dp_aux.c
+++ b/drivers/gpu/drm/msm/dp/dp_aux.c
@@ -162,45 +162,78 @@  static ssize_t dp_aux_cmd_fifo_rx(struct dp_aux_private *aux,
 	return i;
 }
 
-static void dp_aux_native_handler(struct dp_aux_private *aux, u32 isr)
+static irqreturn_t dp_aux_native_handler(struct dp_aux_private *aux, u32 isr)
 {
-	if (isr & DP_INTR_AUX_I2C_DONE)
+	irqreturn_t ret = IRQ_NONE;
+
+	if (isr & DP_INTR_AUX_I2C_DONE) {
 		aux->aux_error_num = DP_AUX_ERR_NONE;
-	else if (isr & DP_INTR_WRONG_ADDR)
+		ret = IRQ_HANDLED;
+	} else if (isr & DP_INTR_WRONG_ADDR) {
 		aux->aux_error_num = DP_AUX_ERR_ADDR;
-	else if (isr & DP_INTR_TIMEOUT)
+		ret = IRQ_HANDLED;
+	} else if (isr & DP_INTR_TIMEOUT) {
 		aux->aux_error_num = DP_AUX_ERR_TOUT;
-	if (isr & DP_INTR_NACK_DEFER)
+		ret = IRQ_HANDLED;
+	}
+
+	if (isr & DP_INTR_NACK_DEFER) {
 		aux->aux_error_num = DP_AUX_ERR_NACK;
+		ret = IRQ_HANDLED;
+	}
+
 	if (isr & DP_INTR_AUX_ERROR) {
 		aux->aux_error_num = DP_AUX_ERR_PHY;
 		dp_catalog_aux_clear_hw_interrupts(aux->catalog);
+		ret = IRQ_HANDLED;
 	}
+
+	return ret;
 }
 
-static void dp_aux_i2c_handler(struct dp_aux_private *aux, u32 isr)
+static irqreturn_t dp_aux_i2c_handler(struct dp_aux_private *aux, u32 isr)
 {
+	irqreturn_t ret = IRQ_NONE;
+
 	if (isr & DP_INTR_AUX_I2C_DONE) {
 		if (isr & (DP_INTR_I2C_NACK | DP_INTR_I2C_DEFER))
 			aux->aux_error_num = DP_AUX_ERR_NACK;
 		else
 			aux->aux_error_num = DP_AUX_ERR_NONE;
-	} else {
-		if (isr & DP_INTR_WRONG_ADDR)
-			aux->aux_error_num = DP_AUX_ERR_ADDR;
-		else if (isr & DP_INTR_TIMEOUT)
-			aux->aux_error_num = DP_AUX_ERR_TOUT;
-		if (isr & DP_INTR_NACK_DEFER)
-			aux->aux_error_num = DP_AUX_ERR_NACK_DEFER;
-		if (isr & DP_INTR_I2C_NACK)
-			aux->aux_error_num = DP_AUX_ERR_NACK;
-		if (isr & DP_INTR_I2C_DEFER)
-			aux->aux_error_num = DP_AUX_ERR_DEFER;
-		if (isr & DP_INTR_AUX_ERROR) {
-			aux->aux_error_num = DP_AUX_ERR_PHY;
-			dp_catalog_aux_clear_hw_interrupts(aux->catalog);
-		}
+
+		return IRQ_HANDLED;
+	}
+
+	if (isr & DP_INTR_WRONG_ADDR) {
+		aux->aux_error_num = DP_AUX_ERR_ADDR;
+		ret = IRQ_HANDLED;
+	} else if (isr & DP_INTR_TIMEOUT) {
+		aux->aux_error_num = DP_AUX_ERR_TOUT;
+		ret = IRQ_HANDLED;
 	}
+
+	if (isr & DP_INTR_NACK_DEFER) {
+		aux->aux_error_num = DP_AUX_ERR_NACK_DEFER;
+		ret = IRQ_HANDLED;
+	}
+
+	if (isr & DP_INTR_I2C_NACK) {
+		aux->aux_error_num = DP_AUX_ERR_NACK;
+		ret = IRQ_HANDLED;
+	}
+
+	if (isr & DP_INTR_I2C_DEFER) {
+		aux->aux_error_num = DP_AUX_ERR_DEFER;
+		ret = IRQ_HANDLED;
+	}
+
+	if (isr & DP_INTR_AUX_ERROR) {
+		aux->aux_error_num = DP_AUX_ERR_PHY;
+		dp_catalog_aux_clear_hw_interrupts(aux->catalog);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
 }
 
 static void dp_aux_update_offset_and_segment(struct dp_aux_private *aux,
@@ -409,29 +442,37 @@  static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
 	return ret;
 }
 
-void dp_aux_isr(struct drm_dp_aux *dp_aux)
+irqreturn_t dp_aux_isr(struct drm_dp_aux *dp_aux)
 {
 	u32 isr;
 	struct dp_aux_private *aux;
+	irqreturn_t ret = IRQ_NONE;
 
 	if (!dp_aux) {
 		DRM_ERROR("invalid input\n");
-		return;
+		return ret;
 	}
 
 	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);
 
 	isr = dp_catalog_aux_get_irq(aux->catalog);
 
+	/* no interrupts pending, return immediately */
+	if (!isr)
+		return ret;
+
 	if (!aux->cmd_busy)
-		return;
+		return ret;
 
 	if (aux->native)
-		dp_aux_native_handler(aux, isr);
+		ret = dp_aux_native_handler(aux, isr);
 	else
-		dp_aux_i2c_handler(aux, isr);
+		ret = dp_aux_i2c_handler(aux, isr);
 
-	complete(&aux->comp);
+	if (ret == IRQ_HANDLED)
+		complete(&aux->comp);
+
+	return ret;
 }
 
 void dp_aux_reconfig(struct drm_dp_aux *dp_aux)
diff --git a/drivers/gpu/drm/msm/dp/dp_aux.h b/drivers/gpu/drm/msm/dp/dp_aux.h
index e930974..511305d 100644
--- a/drivers/gpu/drm/msm/dp/dp_aux.h
+++ b/drivers/gpu/drm/msm/dp/dp_aux.h
@@ -11,7 +11,7 @@ 
 
 int dp_aux_register(struct drm_dp_aux *dp_aux);
 void dp_aux_unregister(struct drm_dp_aux *dp_aux);
-void dp_aux_isr(struct drm_dp_aux *dp_aux);
+irqreturn_t dp_aux_isr(struct drm_dp_aux *dp_aux);
 void dp_aux_init(struct drm_dp_aux *dp_aux);
 void dp_aux_deinit(struct drm_dp_aux *dp_aux);
 void dp_aux_reconfig(struct drm_dp_aux *dp_aux);
diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index 3854c9f..5968ab1 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1982,27 +1982,32 @@  int dp_ctrl_off(struct dp_ctrl *dp_ctrl)
 	return ret;
 }
 
-void dp_ctrl_isr(struct dp_ctrl *dp_ctrl)
+irqreturn_t dp_ctrl_isr(struct dp_ctrl *dp_ctrl)
 {
 	struct dp_ctrl_private *ctrl;
 	u32 isr;
-
-	if (!dp_ctrl)
-		return;
+	irqreturn_t ret = IRQ_NONE;
 
 	ctrl = container_of(dp_ctrl, struct dp_ctrl_private, dp_ctrl);
 
 	isr = dp_catalog_ctrl_get_interrupt(ctrl->catalog);
+	/* no interrupts pending, return immediately */
+	if (!isr)
+		return ret;
 
 	if (isr & DP_CTRL_INTR_READY_FOR_VIDEO) {
 		drm_dbg_dp(ctrl->drm_dev, "dp_video_ready\n");
 		complete(&ctrl->video_comp);
+		ret = IRQ_HANDLED;
 	}
 
 	if (isr & DP_CTRL_INTR_IDLE_PATTERN_SENT) {
 		drm_dbg_dp(ctrl->drm_dev, "idle_patterns_sent\n");
 		complete(&ctrl->idle_comp);
+		ret = IRQ_HANDLED;
 	}
+
+	return ret;
 }
 
 struct dp_ctrl *dp_ctrl_get(struct device *dev, struct dp_link *link,
diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.h b/drivers/gpu/drm/msm/dp/dp_ctrl.h
index 9f29734..c3af06d 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.h
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.h
@@ -25,7 +25,7 @@  int dp_ctrl_off_link_stream(struct dp_ctrl *dp_ctrl);
 int dp_ctrl_off_link(struct dp_ctrl *dp_ctrl);
 int dp_ctrl_off(struct dp_ctrl *dp_ctrl);
 void dp_ctrl_push_idle(struct dp_ctrl *dp_ctrl);
-void dp_ctrl_isr(struct dp_ctrl *dp_ctrl);
+irqreturn_t dp_ctrl_isr(struct dp_ctrl *dp_ctrl);
 void dp_ctrl_handle_sink_request(struct dp_ctrl *dp_ctrl);
 struct dp_ctrl *dp_ctrl_get(struct device *dev, struct dp_link *link,
 			struct dp_panel *panel,	struct drm_dp_aux *aux,
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index bfd0aef..d40bfbd 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -1192,7 +1192,7 @@  static int dp_hpd_event_thread_start(struct dp_display_private *dp_priv)
 static irqreturn_t dp_display_irq_handler(int irq, void *dev_id)
 {
 	struct dp_display_private *dp = dev_id;
-	irqreturn_t ret = IRQ_HANDLED;
+	irqreturn_t ret = IRQ_NONE;
 	u32 hpd_isr_status;
 
 	if (!dp) {
@@ -1206,27 +1206,33 @@  static irqreturn_t dp_display_irq_handler(int irq, void *dev_id)
 		drm_dbg_dp(dp->drm_dev, "type=%d isr=0x%x\n",
 			dp->dp_display.connector_type, hpd_isr_status);
 		/* hpd related interrupts */
-		if (hpd_isr_status & DP_DP_HPD_PLUG_INT_MASK)
+		if (hpd_isr_status & DP_DP_HPD_PLUG_INT_MASK) {
 			dp_add_event(dp, EV_HPD_PLUG_INT, 0, 0);
+			ret = IRQ_HANDLED;
+		}
 
 		if (hpd_isr_status & DP_DP_IRQ_HPD_INT_MASK) {
 			dp_add_event(dp, EV_IRQ_HPD_INT, 0, 0);
+			ret = IRQ_HANDLED;
 		}
 
 		if (hpd_isr_status & DP_DP_HPD_REPLUG_INT_MASK) {
 			dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0);
 			dp_add_event(dp, EV_HPD_PLUG_INT, 0, 3);
+			ret = IRQ_HANDLED;
 		}
 
-		if (hpd_isr_status & DP_DP_HPD_UNPLUG_INT_MASK)
+		if (hpd_isr_status & DP_DP_HPD_UNPLUG_INT_MASK) {
 			dp_add_event(dp, EV_HPD_UNPLUG_INT, 0, 0);
+			ret = IRQ_HANDLED;
+		}
 	}
 
 	/* DP controller isr */
-	dp_ctrl_isr(dp->ctrl);
+	ret |= dp_ctrl_isr(dp->ctrl);
 
 	/* DP aux isr */
-	dp_aux_isr(dp->aux);
+	ret |= dp_aux_isr(dp->aux);
 
 	return ret;
 }