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From: Imre Deak <imre.deak@intel.com>
To: intel-gfx@lists.freedesktop.org
Cc: stable@vger.kernel.org, "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Subject: [PATCH v2 3/3] drm/i915: Disable LTTPR support when the LTTPR rev < 1.4
Date: Wed, 17 Mar 2021 20:49:01 +0200	[thread overview]
Message-ID: <20210317184901.4029798-4-imre.deak@intel.com> (raw)
In-Reply-To: <20210317184901.4029798-1-imre.deak@intel.com>

By the specification the 0xF0000 - 0xF02FF range is only valid if the
LTTPR revision at 0xF0000 is at least 1.4. Disable the LTTPR support
otherwise.

Fixes: 7b2a4ab8b0ef ("drm/i915: Switch to LTTPR transparent mode link training")
Cc: <stable@vger.kernel.org> # v5.11
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 .../gpu/drm/i915/display/intel_dp_link_training.c  | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index d8d90903226f..d92eb192c89d 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -100,17 +100,23 @@ static bool intel_dp_read_lttpr_common_caps(struct intel_dp *intel_dp)
 		return false;
 
 	if (drm_dp_read_lttpr_common_caps(&intel_dp->aux,
-					  intel_dp->lttpr_common_caps) < 0) {
-		intel_dp_reset_lttpr_common_caps(intel_dp);
-		return false;
-	}
+					  intel_dp->lttpr_common_caps) < 0)
+		goto reset_caps;
 
 	drm_dbg_kms(&dp_to_i915(intel_dp)->drm,
 		    "LTTPR common capabilities: %*ph\n",
 		    (int)sizeof(intel_dp->lttpr_common_caps),
 		    intel_dp->lttpr_common_caps);
 
+	/* The minimum value of LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV is 1.4 */
+	if (intel_dp->lttpr_common_caps[0] < 0x14)
+		goto reset_caps;
+
 	return true;
+
+reset_caps:
+	intel_dp_reset_lttpr_common_caps(intel_dp);
+	return false;
 }
 
 static bool
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Imre Deak <imre.deak@intel.com>
To: intel-gfx@lists.freedesktop.org
Cc: stable@vger.kernel.org
Subject: [Intel-gfx] [PATCH v2 3/3] drm/i915: Disable LTTPR support when the LTTPR rev < 1.4
Date: Wed, 17 Mar 2021 20:49:01 +0200	[thread overview]
Message-ID: <20210317184901.4029798-4-imre.deak@intel.com> (raw)
In-Reply-To: <20210317184901.4029798-1-imre.deak@intel.com>

By the specification the 0xF0000 - 0xF02FF range is only valid if the
LTTPR revision at 0xF0000 is at least 1.4. Disable the LTTPR support
otherwise.

Fixes: 7b2a4ab8b0ef ("drm/i915: Switch to LTTPR transparent mode link training")
Cc: <stable@vger.kernel.org> # v5.11
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
---
 .../gpu/drm/i915/display/intel_dp_link_training.c  | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
index d8d90903226f..d92eb192c89d 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
@@ -100,17 +100,23 @@ static bool intel_dp_read_lttpr_common_caps(struct intel_dp *intel_dp)
 		return false;
 
 	if (drm_dp_read_lttpr_common_caps(&intel_dp->aux,
-					  intel_dp->lttpr_common_caps) < 0) {
-		intel_dp_reset_lttpr_common_caps(intel_dp);
-		return false;
-	}
+					  intel_dp->lttpr_common_caps) < 0)
+		goto reset_caps;
 
 	drm_dbg_kms(&dp_to_i915(intel_dp)->drm,
 		    "LTTPR common capabilities: %*ph\n",
 		    (int)sizeof(intel_dp->lttpr_common_caps),
 		    intel_dp->lttpr_common_caps);
 
+	/* The minimum value of LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV is 1.4 */
+	if (intel_dp->lttpr_common_caps[0] < 0x14)
+		goto reset_caps;
+
 	return true;
+
+reset_caps:
+	intel_dp_reset_lttpr_common_caps(intel_dp);
+	return false;
 }
 
 static bool
-- 
2.25.1

_______________________________________________
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Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

  parent reply	other threads:[~2021-03-17 18:49 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-17 18:48 [PATCH v2 0/3] drm/i915: Fix DP LTTPR link training mode initialization Imre Deak
2021-03-17 18:48 ` [Intel-gfx] " Imre Deak
2021-03-17 18:48 ` [PATCH v2 1/3] drm/i915/ilk-glk: Fix link training on links with LTTPRs Imre Deak
2021-03-17 18:48   ` [Intel-gfx] " Imre Deak
2021-03-18 17:33   ` Ville Syrjälä
2021-03-18 17:33     ` [Intel-gfx] " Ville Syrjälä
2021-03-18 17:49     ` Imre Deak
2021-03-18 17:49       ` [Intel-gfx] " Imre Deak
2021-03-18 18:06       ` Imre Deak
2021-03-18 18:06         ` [Intel-gfx] " Imre Deak
2021-03-18 22:04         ` Almahallawy, Khaled
2021-03-18 22:04           ` [Intel-gfx] " Almahallawy, Khaled
2021-03-18 23:17           ` Imre Deak
2021-03-18 23:17             ` [Intel-gfx] " Imre Deak
2021-03-19 17:25             ` Lyude Paul
2021-03-19 17:25               ` [Intel-gfx] " Lyude Paul
2021-03-19 17:29               ` Imre Deak
2021-03-19 17:29                 ` [Intel-gfx] " Imre Deak
2021-03-19 20:44                 ` Lyude Paul
2021-03-19 20:44                   ` [Intel-gfx] " Lyude Paul
2021-03-19 21:07                   ` Imre Deak
2021-03-19 21:07                     ` [Intel-gfx] " Imre Deak
2021-03-20  7:15                     ` Imre Deak
2021-03-20  7:15                       ` [Intel-gfx] " Imre Deak
2021-03-20  7:40                       ` Almahallawy, Khaled
2021-03-20  7:40                         ` [Intel-gfx] " Almahallawy, Khaled
2021-03-20  7:45                         ` Imre Deak
2021-03-20  7:45                           ` [Intel-gfx] " Imre Deak
2021-03-17 18:49 ` [PATCH v2 2/3] drm/i915: Disable LTTPR support when the DPCD rev < 1.4 Imre Deak
2021-03-17 18:49   ` [Intel-gfx] " Imre Deak
2021-03-17 19:01   ` Imre Deak
2021-03-17 19:01     ` [Intel-gfx] " Imre Deak
2021-03-18 17:57     ` Ville Syrjälä
2021-03-18 17:57       ` [Intel-gfx] " Ville Syrjälä
2021-03-18 18:05       ` Imre Deak
2021-03-18 18:05         ` [Intel-gfx] " Imre Deak
2021-03-17 18:49 ` Imre Deak [this message]
2021-03-17 18:49   ` [Intel-gfx] [PATCH v2 3/3] drm/i915: Disable LTTPR support when the LTTPR " Imre Deak
2021-03-18 18:00   ` Ville Syrjälä
2021-03-18 18:00     ` [Intel-gfx] " Ville Syrjälä
2021-03-18 18:09     ` Imre Deak
2021-03-18 18:09       ` [Intel-gfx] " Imre Deak
2021-03-17 20:26 ` [Intel-gfx] ✓ Fi.CI.BAT: success for drm/i915: Fix DP LTTPR link training mode initialization (rev2) Patchwork
2021-03-17 21:01 ` [Intel-gfx] drm/i915: Fix DP LTTPR link training mode initialization Zephaniah E. Loss-Cutler-Hull
2021-03-17 22:34 ` [Intel-gfx] ✓ Fi.CI.IGT: success for drm/i915: Fix DP LTTPR link training mode initialization (rev2) Patchwork
2021-03-19 11:16   ` Imre Deak
2021-03-19 11:16     ` [Intel-gfx] " Imre Deak
2021-03-22  8:34 ` [Intel-gfx] drm/i915: Fix DP LTTPR link training mode initialization Zephaniah E. Loss-Cutler-Hull

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