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From: Nathan Schulte <nmschulte@gmail.com>
To: intel-gfx@lists.freedesktop.org
Subject: [PATCH] [i915] add module param "enable_dp_mst"
Date: Mon, 14 Mar 2016 11:36:29 -0500	[thread overview]
Message-ID: <1457973389-15097-2-git-send-email-nmschulte@gmail.com> (raw)
In-Reply-To: <1457973389-15097-1-git-send-email-nmschulte@gmail.com>

Adds an (unsafe; auto-kernel-tainting) boolean module parameter to the i915
drm driver: "enable_dp_mst", which is enabled by default.  Disabling the
parameter forces newly connected DisplayPort sinks to report as not
supporting multi-stream transport (MST), thus "forcing" the use of
single-stream transport (SST).
---
 drivers/gpu/drm/i915/i915_params.c | 5 +++++
 drivers/gpu/drm/i915/i915_params.h | 1 +
 drivers/gpu/drm/i915/intel_dp.c    | 3 +++
 3 files changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 278c9c4..97691f1 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -56,6 +56,7 @@ struct i915_params i915 __read_mostly = {
 	.edp_vswing = 0,
 	.enable_guc_submission = false,
 	.guc_log_level = -1,
+	.enable_dp_mst = true,
 };
 
 module_param_named(modeset, i915.modeset, int, 0400);
@@ -201,3 +202,7 @@ MODULE_PARM_DESC(enable_guc_submission, "Enable GuC submission (default:false)")
 module_param_named(guc_log_level, i915.guc_log_level, int, 0400);
 MODULE_PARM_DESC(guc_log_level,
 	"GuC firmware logging level (-1:disabled (default), 0-3:enabled)");
+
+module_param_named_unsafe(enable_dp_mst, i915.enable_dp_mst, bool, 0600);
+MODULE_PARM_DESC(enable_dp_mst,
+	"Enable multi-stream transport (MST) for new DisplayPort sinks. (default: true)");
diff --git a/drivers/gpu/drm/i915/i915_params.h b/drivers/gpu/drm/i915/i915_params.h
index bd5026b..87153b0 100644
--- a/drivers/gpu/drm/i915/i915_params.h
+++ b/drivers/gpu/drm/i915/i915_params.h
@@ -59,6 +59,7 @@ struct i915_params {
 	bool enable_guc_submission;
 	bool verbose_state_checks;
 	bool nuclear_pageflip;
+	bool enable_dp_mst;
 };
 
 extern struct i915_params i915 __read_mostly;
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 0e326e7..ba2d024 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3882,6 +3882,9 @@ intel_dp_probe_mst(struct intel_dp *intel_dp)
 {
 	u8 buf[1];
 
+	if (!i915.enable_dp_mst)
+		return false;
+
 	if (!intel_dp->can_mst)
 		return false;
 
-- 
2.7.0

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  reply	other threads:[~2016-03-14 16:36 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-10 23:43 i915: allow forcing SST on DisplayPort connectors Nathan Schulte
2016-03-10 23:43 ` [PATCH 1/2] [i915] add module param "force_dp_sst" Nathan Schulte
2016-03-11 13:45   ` Jani Nikula
2016-03-10 23:43 ` [PATCH 2/2] [i915] move bools to end of i915_params struct Nathan Schulte
2016-03-11  7:40 ` ✗ Fi.CI.BAT: failure for series starting with [1/2,i915] add module param "force_dp_sst" Patchwork
2016-03-11  8:47   ` Joonas Lahtinen
2016-03-14 16:36 ` [PATCH v2] i915: module param to disable DisplayPort MST Nathan Schulte
2016-03-14 16:36   ` Nathan Schulte [this message]
2016-03-15  8:43     ` [PATCH] [i915] add module param "enable_dp_mst" Daniel Vetter
2016-03-15 15:14   ` [PATCH v3] drm/i915: " Nathan Schulte
2016-03-16 15:40     ` Daniel Vetter

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