Attachment 110360 Details for Bug 86936 – Add a module parameter for overriding minimum brightness control

[patch] Add a module parameter for overriding minimum brightness control

0001-drm-i915-Allow-overriding-minimum-brightness-control.patch (text/plain), 3.40 KB, created by Aurabindo J on 2014-12-02 15:39:18 UTC

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Creator: Aurabindo J

Created: 2014-12-02 15:39:18 UTC

Size: 3.40 KB

patch

obsolete

>From 1599bfdb72a7650e58642348438af8887fc9ee20 Mon Sep 17 00:00:00 2001
>From: Jay Aurabind <mail@aurabindo.in>
>Date: Sat, 29 Nov 2014 00:06:05 +0530
>Subject: [PATCH] drm/i915: Allow overriding minimum brightness control
>
>Provide provision for users to disable restriction on minimum brightness
>value introduced in:
>
>    commit e1c412e75754ab7b7002f3e18a2652d999c40d4b
>    Author: Jani Nikula <jani.nikula@intel.com>
>    Date:   Wed Nov 5 14:46:31 2014 +0200
>
>        drm/i915: safeguard against too high minimum brightness
>
>There are systems which work reliably without restriction on minimum
>value of display brightness. Also the arbitrary value may be too high
>for many users as well.
>
>Signed-off-by: Aurabindo J <mail@aurabindo.in>
>---
> drivers/gpu/drm/i915/i915_drv.h    |  1 +
> drivers/gpu/drm/i915/i915_params.c |  6 ++++++
> drivers/gpu/drm/i915/intel_panel.c | 14 ++++++++++----
> 3 files changed, 17 insertions(+), 4 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>index 16a6f6d..55d2ead 100644
>--- a/drivers/gpu/drm/i915/i915_drv.h
>+++ b/drivers/gpu/drm/i915/i915_drv.h
>@@ -2213,6 +2213,7 @@ struct i915_params {
> 	int disable_power_well;
> 	int enable_ips;
> 	int invert_brightness;
>+	int restrict_min_brightness;
> 	int enable_cmd_parser;
> 	/* leave bools at the end to not create holes */
> 	bool enable_hangcheck;
>diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
>index c91cb20..0601c2a 100644
>--- a/drivers/gpu/drm/i915/i915_params.c
>+++ b/drivers/gpu/drm/i915/i915_params.c
>@@ -46,6 +46,7 @@ struct i915_params i915 __read_mostly = {
> 	.prefault_disable = 0,
> 	.reset = true,
> 	.invert_brightness = 0,
>+	.restrict_min_brightness = 1,
> 	.disable_display = 0,
> 	.enable_cmd_parser = 1,
> 	.disable_vtd_wa = 0,
>@@ -155,6 +156,11 @@ MODULE_PARM_DESC(invert_brightness,
> 	"to dri-devel@lists.freedesktop.org, if your machine needs it. "
> 	"It will then be included in an upcoming module version.");
> 
>+module_param_named(restrict_min_brightness, i915.restrict_min_brightness, int, 0600);
>+MODULE_PARM_DESC(restrict_min_brightness,
>+	"Restrict minimum brightness "
>+	"(-1 disable restriction, 0 value from VBT, 1 arbitrary value )");
>+
> module_param_named(disable_display, i915.disable_display, bool, 0600);
> MODULE_PARM_DESC(disable_display, "Disable display (default: false)");
> 
>diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
>index 41b3be2..def9f4e 100644
>--- a/drivers/gpu/drm/i915/intel_panel.c
>+++ b/drivers/gpu/drm/i915/intel_panel.c
>@@ -1109,10 +1109,16 @@ static u32 get_backlight_min_vbt(struct intel_connector *connector)
> 	 * against this by letting the minimum be at most (arbitrarily chosen)
> 	 * 25% of the max.
> 	 */
>-	min = clamp_t(int, dev_priv->vbt.backlight.min_brightness, 0, 64);
>-	if (min != dev_priv->vbt.backlight.min_brightness) {
>-		DRM_DEBUG_KMS("clamping VBT min backlight %d/255 to %d/255\n",
>-			      dev_priv->vbt.backlight.min_brightness, min);
>+	if (i915.restrict_min_brightness < 0)
>+		min = 0;
>+	else if (i915.restrict_min_brightness == 0)
>+		min = dev_priv->vbt.backlight.min_brightness;
>+	else {
>+		min = clamp_t(int, dev_priv->vbt.backlight.min_brightness, 0, 64);
>+		if (min != dev_priv->vbt.backlight.min_brightness) {
>+			DRM_DEBUG_KMS("clamping VBT min backlight %d/255 to %d/255\n",
>+					dev_priv->vbt.backlight.min_brightness, min);
>+	    }
> 	}
> 
> 	/* vbt value is a coefficient in range [0..255] */
>-- 
>2.1.3
>

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