Attachment 26665 Details for Bug 21496 – 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), 3.64 KB, created by ykzhao on 2009-06-11 02:04:27 UTC

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Creator: ykzhao

Created: 2009-06-11 02:04:27 UTC

Size: 3.64 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 |   65 ++++++++++++++++++++++++++++++++++++++
> 1 file changed, 65 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 16:39:32.000000000 +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.
>@@ -505,6 +506,59 @@
> };
> 
> /**
>+ * check_lid_device -- check whether it is ACPI LID device.
>+ * @dev: the ACPI device
>+ * @data: the number of LID device
>+ *
>+ * check whether it is a LID device by comparing the HID. If it is,
>+ * increase the number of LID device.
>+ */
>+static int check_lid_device(struct device *dev, void *data)
>+{
>+#define		ACPI_HID_LID		"PNP0C0D"
>+	struct acpi_device *acpi_dev;
>+	int *p_lid = (int *)data;
>+
>+	acpi_dev = to_acpi_device(dev);
>+	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 0;
>+}
>+/**
>+ * 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;
>+	}
>+
>+	bus_for_each_dev(&acpi_bus_type, NULL, &lid_count, check_lid_device);
>+
>+	if (!lid_count) {
>+		/* No LID device is not found. Return -ENODEV */
>+		return -ENODEV;
>+	}
>+
>+	return 0;
>+}
>+/**
>  * intel_lvds_init - setup LVDS connectors on this device
>  * @dev: drm device
>  *
>@@ -526,6 +580,17 @@
> 	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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Attachments on bug 21496: 25319 | 25320 | 26227 | 26228 | 26554 | 26555 | 26556 | 26665 | 28707 | 28708

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