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* [Intel-gfx] [PATCH] drm/i915/mtl: Clear possible sticky bits on PICA message bus
@ 2023-11-01 10:31 Mika Kahola
  2023-11-01 10:51 ` Jani Nikula
                   ` (3 more replies)
  0 siblings, 4 replies; 10+ messages in thread
From: Mika Kahola @ 2023-11-01 10:31 UTC (permalink / raw)
  To: intel-gfx

It is possible that sticky bits or error bits are left on
message bus status register. Reading and then writing the
value back to messagebus status register clears all possible
sticky bits and errors.

Signed-off-by: Mika Kahola <mika.kahola@intel.com>
---
 drivers/gpu/drm/i915/display/intel_cx0_phy.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.c b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
index b2ad4c6172f6..f439f0c7b400 100644
--- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
@@ -195,6 +195,13 @@ static int __intel_cx0_read_once(struct drm_i915_private *i915, enum port port,
 		return -ETIMEDOUT;
 	}
 
+	/*
+	 * write XELPDP_PORT_P2M_MSGBUS_STATUS register after read to clear
+	 * any error sticky bits set from previous transactions
+	 */
+	val = intel_de_read(i915, XELPDP_PORT_P2M_MSGBUS_STATUS(port, lane));
+	intel_de_write(i915, XELPDP_PORT_P2M_MSGBUS_STATUS(port, lane), val);
+
 	intel_de_write(i915, XELPDP_PORT_M2P_MSGBUS_CTL(port, lane),
 		       XELPDP_PORT_M2P_TRANSACTION_PENDING |
 		       XELPDP_PORT_M2P_COMMAND_READ |
@@ -262,6 +269,13 @@ static int __intel_cx0_write_once(struct drm_i915_private *i915, enum port port,
 		return -ETIMEDOUT;
 	}
 
+	/*
+	 * write XELPDP_PORT_P2M_MSGBUS_STATUS register after read to clear
+	 * any error sticky bits set from previous transactions
+	 */
+	val = intel_de_read(i915, XELPDP_PORT_P2M_MSGBUS_STATUS(port, lane));
+	intel_de_write(i915, XELPDP_PORT_P2M_MSGBUS_STATUS(port, lane), val);
+
 	intel_de_write(i915, XELPDP_PORT_M2P_MSGBUS_CTL(port, lane),
 		       XELPDP_PORT_M2P_TRANSACTION_PENDING |
 		       (committed ? XELPDP_PORT_M2P_COMMAND_WRITE_COMMITTED :
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2023-11-03 15:00 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-11-01 10:31 [Intel-gfx] [PATCH] drm/i915/mtl: Clear possible sticky bits on PICA message bus Mika Kahola
2023-11-01 10:51 ` Jani Nikula
2023-11-01 11:08   ` Ville Syrjälä
2023-11-01 13:21   ` Kahola, Mika
2023-11-01 13:30 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
2023-11-02 13:12 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
2023-11-02 14:23 ` [Intel-gfx] [PATCH] " Gustavo Sousa
2023-11-02 14:54   ` Kahola, Mika
2023-11-03 14:47     ` Kahola, Mika
2023-11-03 15:00       ` Kahola, Mika

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