This is a note to let you know that I've just added the patch titled
drm/i915: Assume dual channel LVDS if pixel clock necessitates it
to the 4.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-i915-assume-dual-channel-lvds-if-pixel-clock-necessitates-it.patch
and it can be found in the queue-4.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6f317cfe42c9d8a7c9c1a327d2f1bcc517a3cd91 Mon Sep 17 00:00:00 2001
From: Lukas Wunner <lukas@xxxxxxxxx>
Date: Sun, 12 Apr 2015 21:10:35 +0200
Subject: drm/i915: Assume dual channel LVDS if pixel clock necessitates it
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
From: Lukas Wunner <lukas@xxxxxxxxx>
commit 6f317cfe42c9d8a7c9c1a327d2f1bcc517a3cd91 upstream.
Single channel LVDS maxes out at 112 MHz, anything above must be dual
channel. This avoids the need to specify i915.lvds_channel_mode=2 on
all 17" MacBook Pro models with i915 graphics since they had 1920x1200
(193 MHz), plus those 15" pre-retina models which had a resolution
of 1680x1050 (119 MHz) as a BTO option.
Source for 112 MHz limit of single channel LVDS is section 2.3 of:
https://01.org/linuxgraphics/sites/default/files/documentation/ivb_ihd_os_vol3_part4.pdf
v2: Avoid hardcoding 17" models by assuming dual channel LVDS if the
resolution necessitates it, suggested by Jani Nikula.
v3: Fix typo, thanks Joonas Lahtinen.
v4: Split commit in two, suggested by Ville Syrjälä.
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Tested-by: Lukas Wunner <lukas@xxxxxxxxx>
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
[Jani: included spec reference into the commit message]
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_lvds.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -847,6 +847,11 @@ static bool compute_is_dual_link_lvds(st
if (i915.lvds_channel_mode > 0)
return i915.lvds_channel_mode == 2;
+ /* single channel LVDS is limited to 112 MHz */
+ if (lvds_encoder->attached_connector->base.panel.fixed_mode->clock
+ > 112999)
+ return true;
+
if (dmi_check_system(intel_dual_link_lvds))
return true;
@@ -1104,6 +1109,8 @@ void intel_lvds_init(struct drm_device *
out:
mutex_unlock(&dev->mode_config.mutex);
+ intel_panel_init(&intel_connector->panel, fixed_mode, downclock_mode);
+
lvds_encoder->is_dual_link = compute_is_dual_link_lvds(lvds_encoder);
DRM_DEBUG_KMS("detected %s-link lvds configuration\n",
lvds_encoder->is_dual_link ? "dual" : "single");
@@ -1118,7 +1125,6 @@ out:
}
drm_connector_register(connector);
- intel_panel_init(&intel_connector->panel, fixed_mode, downclock_mode);
intel_panel_setup_backlight(connector, INVALID_PIPE);
return;
Patches currently in stable-queue which might be from lukas@xxxxxxxxx are
queue-4.0/drm-i915-assume-dual-channel-lvds-if-pixel-clock-necessitates-it.patch
queue-4.0/drm-i915-add-missing-macbook-pro-models-with-dual-channel-lvds.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html