Attachment 26826 Details for Bug 21856 – Use the LID device to decide whether the LVDS device should be initialized

[patch] Use the LID device to decide whether the LVDS device should be initialized

lvds_lid.patch (text/plain), 4.16 KB, created by ykzhao on 2009-06-16 01:38:50 UTC

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Creator: ykzhao

Created: 2009-06-16 01:38:50 UTC

Size: 4.16 KB

patch

obsolete

>Subject:[DRM/I915]: Use the LID device to decide whether the LVDS should be initialized
>From: Zhao Yakui <yakui.zhao@intel.com>
>
>On some boxes the mobile chipset is used and there is no LVDS device. In such
>case we had better not initialize the LVDS output device so that one pipe can
>be used for other output device. For example: E-TOP.
>
>But unfortunately the LVDS device is still initialized on the boxes based on
>mobile chipset in KMS mode. It brings that this pipe occupied by LVDS can't be
>used for other output device.
>
>After checking the acpidump we find that there is no LID device on such boxes.
>In such case we can use the LID device to decide whether the LVDS device should
>be initialized. 
>
>If there is no LID device, we can think that there is no LVDS device. It is
>unnecessary to initialize the LVDS output device.
>If there exists the LID device, it will continue the current flowchart.
>
>Maybe on some boxes there is no LVDS device but the LID device is found. In
>such case it had better be added to the quirk table.
>
>http://bugs.freedesktop.org/show_bug.cgi?id=21496
>
>Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
>---
> drivers/gpu/drm/i915/intel_lvds.c |   79 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 79 insertions(+)
>
>Index: linux-2.6/drivers/gpu/drm/i915/intel_lvds.c
>===================================================================
>--- linux-2.6.orig/drivers/gpu/drm/i915/intel_lvds.c	2009-06-11 15:27:07.000000000 +0800
>+++ linux-2.6/drivers/gpu/drm/i915/intel_lvds.c	2009-06-11 17:42:07.000000000 +0800
>@@ -36,6 +36,7 @@
> #include "intel_drv.h"
> #include "i915_drm.h"
> #include "i915_drv.h"
>+#include <linux/acpi.h>
> 
> /**
>  * Sets the backlight level.
>@@ -503,7 +504,74 @@
> 
> 	{ }	/* terminating entry */
> };
>+#ifdef CONFIG_ACPI
>+/*
>+ * check_lid_device -- check whether it is ACPI LID device.
>+ * @handle: ACPI device handle
>+ * @level : depth in the ACPI namespace tree
>+ * @context: the number of LID device when we find the device
>+ * @rv: a return value to fill if desired (Not use)
>+ *
>+ * check whether it is a LID device by comparing the HID. If it is,
>+ * increase the number of LID device.
>+ */
>+static acpi_status
>+check_lid_device(acpi_handle handle, u32 level, void *context,
>+			void **retyurn_value)
>+{
>+#define		ACPI_HID_LID		"PNP0C0D"
>+	struct acpi_device *acpi_dev;
>+	int *p_lid = (int *)context;
>+
>+	acpi_dev = NULL;
>+	/* Get the acpi device for device handle */
>+	if (acpi_bus_get_device(handle, &acpi_dev) || !acpi_dev) {
>+		/* If there is no ACPI device for handle, return */
>+		return AE_OK;
>+	}
>+	if (!strncmp(acpi_device_hid(acpi_dev), ACPI_HID_LID, 7)) {
>+		/*
>+		 * compare the device HID with "PNP0C0D". If it is equal, the
>+		 * LID device is found. Increase the count
>+		 */
>+		(*p_lid)++;
>+	}
>+	return AE_OK;
>+}
>+/**
>+ * check whether there exists the ACPI LID device by enumerating the ACPI
>+ * device tree.
>+ * If ACPI is disabled, there is no ACPI device tree. 0 is returned.
>+ * If the LID device is found, it will return zero.
>+ * If no LID device is found, it will return  -ENODEV.
>+ */
>+static int intel_lvds_find_lid(void)
>+{
>+	int lid_count = 0;
> 
>+	if (acpi_disabled) {
>+		/*
>+		 * if ACPI is disabled, there is no ACPI device tree. And
>+		 * we don't know whether there exists the LID device.
>+		 * In such case we will return 0.
>+		 */
>+		return 0;
>+	}
>+
>+	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
>+				ACPI_UINT32_MAX,
>+				check_lid_device, &lid_count, NULL);
>+
>+	if (!lid_count) {
>+		/* No LID device is not found. Return -ENODEV */
>+		return -ENODEV;
>+	}
>+
>+	return 0;
>+}
>+#else
>+static inline int intel_lvds_find_lid(void) { return 0; }
>+#endif
> /**
>  * intel_lvds_init - setup LVDS connectors on this device
>  * @dev: drm device
>@@ -526,6 +594,17 @@
> 	if (dmi_check_system(intel_no_lvds))
> 		return;
> 
>+	if (intel_lvds_find_lid()) {
>+		/* If there is no LID device, we can think that there is
>+		 * no LVDS output device. In such case it is unnecessary to
>+		 * create the LVDS output device.
>+		 * But maybe on some boxes there is no LVDS device while the
>+		 * LID device is found. If so, it had better be added to
>+		 * the quirk list.
>+		 */
>+		return;
>+	}
>+
> 	if (IS_IGDNG(dev)) {
> 		if ((I915_READ(PCH_LVDS) & LVDS_DETECTED) == 0)
> 			return;

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