From 7cc96139d9e3f627bd18e5ee6a5e4e305369865b Mon Sep 17 00:00:00 2001 From: Nathan Schulte Date: Tue, 15 Mar 2016 10:14:05 -0500 Subject: [PATCH] drm/i915: add module param "enable_dp_mst" 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). v2: rename parameter to conform to style v3: add signoff Signed-off-by: Nathan Schulte Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/1458054845-5837-1-git-send-email-nmschulte@gmail.com --- 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 278c9c40c2e0..97691f1f679c 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 bd5026b15d3e..87153b0199cd 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 0e326e776e8f..ba2d0242d532 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; -- 2.20.1