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* [Intel-gfx] [PATCH v3] drm/i915/display: Reset message bus after each read/write operation
@ 2023-10-16 12:55 Mika Kahola
  2023-10-16 18:10 ` Rodrigo Vivi
                   ` (9 more replies)
  0 siblings, 10 replies; 12+ messages in thread
From: Mika Kahola @ 2023-10-16 12:55 UTC (permalink / raw)
  To: intel-gfx; +Cc: rodrigo.vivi

Every know and then we receive the following error when running
for example IGT test kms_flip.

[drm] *ERROR* PHY G Read 0d80 failed after 3 retries.
[drm] *ERROR* PHY G Write 0d81 failed after 3 retries.

Since the error is sporadic in nature, the patch proposes
to reset the message bus after every successful or unsuccessful
read or write operation.

v2: Add FIXME's to indicate the experimental nature of
    this workaround (Rodrigo)
v3: Dropping the additional delay as moving reset to *_read_once()
    and *_write_once() functions seem unnecessary delay

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 6e6a1818071e..9e24f820d4cf 100644
--- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
@@ -206,6 +206,13 @@ static int __intel_cx0_read_once(struct drm_i915_private *i915, enum port port,
 
 	intel_clear_response_ready_flag(i915, port, lane);
 
+	/*
+	 * FIXME: Workaround to let HW to settle
+	 * down and let the message bus to end up
+	 * in a known state
+	 */
+	intel_cx0_bus_reset(i915, port, lane);
+
 	return REG_FIELD_GET(XELPDP_PORT_P2M_DATA_MASK, val);
 }
 
@@ -285,6 +292,13 @@ static int __intel_cx0_write_once(struct drm_i915_private *i915, enum port port,
 
 	intel_clear_response_ready_flag(i915, port, lane);
 
+	/*
+	 * FIXME: Workaround to let HW to settle
+	 * down and let the message bus to end up
+	 * in a known state
+	 */
+	intel_cx0_bus_reset(i915, port, lane);
+
 	return 0;
 }
 
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2023-10-25  5:29 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-10-16 12:55 [Intel-gfx] [PATCH v3] drm/i915/display: Reset message bus after each read/write operation Mika Kahola
2023-10-16 18:10 ` Rodrigo Vivi
2023-10-17  2:28 ` [Intel-gfx] ✗ Fi.CI.BAT: failure for drm/i915/display: Reset message bus after each read/write operation (rev4) Patchwork
2023-10-17  6:53   ` Kahola, Mika
2023-10-17 13:33 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2023-10-17 16:15 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
2023-10-18 21:20 ` [Intel-gfx] ✓ Fi.CI.BAT: success for drm/i915/display: Reset message bus after each read/write operation (rev5) Patchwork
2023-10-19  0:08 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
2023-10-19 11:38 ` Patchwork
2023-10-19 12:06 ` Patchwork
2023-10-19 12:51 ` Patchwork
2023-10-25  5:29 ` [Intel-gfx] ✓ Fi.CI.IGT: success " Patchwork

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