i915 native backlight (resend for intel-gfx)

[Jean-Francois Dagenais <jeff.dagenais@gmail.com>]

Hi all,

I had a patch from Matthew Garrett a little while back called "i915: Add native backlight control" which I added straight onto v2.6.37 (plus a minor include tweak to make compile if I remember correctly) And it worked with my setup. Using a Kontron ETXexpress-PC (ETXexpress®-PC with GS45 chipset, Intel® Core™2 Duo SU 9300. In the BIOS setup, the setting for backlight is indeed set to "PWM". From what I understand, this a pin straight from the COM slot which carries a PWM dutycycle that we send to the panel we attachusing the JILI (Jumptech Intelligent lvds interface) panel connector.

Now with the most recent kernel I thought I could drop the patch and use the tree as is for backlight since commit aaa6fd2a004 again from Matthew seems to contain a more recent version of the work.

Unfortunately, intel_backlight isn't doing anything on my board anymore.

Which steps would you recommend to help me find and resolve the issue?

Thanks for the help!
/jfd


FYI, here's the patch I had applied onto v2.6.37:

From: Matthew Garrett <mjg@redhat.com>
Date: Fri, 19 Nov 2010 15:53:53 +0000
Subject: [PATCH 1/2] i915: Add native backlight control (tweaked by JFD to
make compile)

Not all systems expose a firmware or platform mechanism for changing the
backlight intensity on i915, so add native driver support.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: intel-gfx <intel-gfx@lists.freedesktop.org>
---
drivers/gpu/drm/i915/i915_drv.h       |    4 ++
drivers/gpu/drm/i915/intel_dp.c       |    7 +++
drivers/gpu/drm/i915/intel_drv.h      |    2 +
drivers/gpu/drm/i915/intel_lvds.c     |    5 ++
drivers/gpu/drm/i915/intel_opregion.c |    1 -
drivers/gpu/drm/i915/intel_panel.c    |   66 +++++++++++++++++++++++++++++++++
6 files changed, 84 insertions(+), 1 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 409826d..9edf650 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -36,6 +36,7 @@
#include <linux/io-mapping.h>
#include <linux/i2c.h>
#include <drm/intel-gtt.h>
+#include <linux/backlight.h>

/* General customization:
 */
@@ -679,6 +680,7 @@ typedef struct drm_i915_private {
	int child_dev_num;
	struct child_device_config *child_dev;
	struct drm_connector *int_lvds_connector;
+	struct drm_connector *int_edp_connector;

	bool mchbar_need_disable;

@@ -707,6 +709,8 @@ typedef struct drm_i915_private {

	/* list of fbdev register on this device */
	struct intel_fbdev *fbdev;
+
+	struct backlight_device *backlight;
} drm_i915_private_t;

/** driver private structure attached to each drm_gem_object */
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 864417c..2c114e0 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1655,6 +1655,11 @@ done:
static void
intel_dp_destroy (struct drm_connector *connector)
{
+	struct drm_device *dev = connector->dev;
+
+	if (intel_dpd_is_edp(dev))
+		intel_panel_backlight_destroy(dev);
+
	drm_sysfs_connector_remove(connector);
	drm_connector_cleanup(connector);
	kfree(connector);
@@ -1884,6 +1889,8 @@ intel_dp_init(struct drm_device *dev, int output_reg)
					DRM_MODE_TYPE_PREFERRED;
			}
		}
+		dev_priv->int_edp_connector = connector;
+		intel_panel_backlight_setup(dev);
	}

	intel_dp_add_properties(intel_dp, connector);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index e52c612..6f55e81 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -256,6 +256,8 @@ extern void intel_pch_panel_fitting(struct drm_device *dev,
extern u32 intel_panel_get_max_backlight(struct drm_device *dev);
extern u32 intel_panel_get_backlight(struct drm_device *dev);
extern void intel_panel_set_backlight(struct drm_device *dev, u32 level);
+extern int intel_panel_backlight_setup(struct drm_device *dev);
+extern void intel_panel_backlight_destroy(struct drm_device *dev);

extern void intel_crtc_load_lut(struct drm_crtc *crtc);
extern void intel_encoder_prepare (struct drm_encoder *encoder);
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 25bcedf..ae1b5e3 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -579,6 +579,8 @@ static void intel_lvds_destroy(struct drm_connector *connector)
	struct drm_device *dev = connector->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;

+	intel_panel_backlight_destroy(dev);
+
	if (dev_priv->lid_notifier.notifier_call)
		acpi_lid_notifier_unregister(&dev_priv->lid_notifier);
	drm_sysfs_connector_remove(connector);
@@ -1036,6 +1038,9 @@ out:
	/* keep the LVDS connector */
	dev_priv->int_lvds_connector = connector;
	drm_sysfs_connector_add(connector);
+
+	intel_panel_backlight_setup(dev);
+
	return true;

failed:
diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
index 9b0d9a8..bf79c02 100644
--- a/drivers/gpu/drm/i915/intel_opregion.c
+++ b/drivers/gpu/drm/i915/intel_opregion.c
@@ -224,7 +224,6 @@ void intel_opregion_asle_intr(struct drm_device *dev)
	asle->aslc = asle_stat;
}

-/* Only present on Ironlake+ */
void intel_opregion_gse_intr(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 92ff8f3..eec0f79 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -218,3 +218,69 @@ void intel_panel_set_backlight(struct drm_device *dev, u32 level)
		tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK;
	I915_WRITE(BLC_PWM_CTL, tmp | level);
}
+
+#ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
+static int intel_panel_update_status(struct backlight_device *bd)
+{
+	struct drm_device *dev = bl_get_data(bd);
+	intel_panel_set_backlight(dev, bd->props.brightness);
+	return 0;
+}
+
+static int intel_panel_get_brightness(struct backlight_device *bd)
+{
+	struct drm_device *dev = bl_get_data(bd);
+	return intel_panel_get_backlight(dev);
+}
+
+static const struct backlight_ops intel_panel_bl_ops = {
+	.update_status = intel_panel_update_status,
+	.get_brightness = intel_panel_get_brightness,
+};
+
+int intel_panel_backlight_setup(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct backlight_properties props;
+	struct drm_connector *connector;
+
+	if (dev_priv->int_lvds_connector)
+		connector = dev_priv->int_lvds_connector;
+	else if (dev_priv->int_edp_connector)
+		connector = dev_priv->int_edp_connector;
+	else
+		return -ENODEV;
+
+	props.max_brightness = intel_panel_get_max_backlight(dev);
+	dev_priv->backlight =
+		backlight_device_register("intel_backlight",
+					  &connector->kdev, dev,
+					  &intel_panel_bl_ops, &props);
+
+	if (IS_ERR(dev_priv->backlight)) {
+		DRM_ERROR("Failed to register backlight: %ld\n",
+			  PTR_ERR(dev_priv->backlight));
+		dev_priv->backlight = NULL;
+		return -ENODEV;
+	}
+	dev_priv->backlight->props.brightness = intel_panel_get_backlight(dev);
+	return 0;
+}
+
+void intel_panel_backlight_destroy(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	if (dev_priv->backlight)
+		backlight_device_unregister(dev_priv->backlight);
+}
+#else
+int intel_panel_backlight_setup(struct drm_device *dev)
+{
+	return 0;
+}
+
+void intel_panel_backlight_destroy(struct drm_device *dev)
+{
+	return;
+}
+#endif
-- 
1.7.6.1