62 lines
2.3 KiB
Diff
62 lines
2.3 KiB
Diff
From: Aaron Lu <aaron.lu@intel.com>
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Date: Tue, 28 Oct 2014 14:35:59 +0800
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Subject: ACPI / video: Run _BCL before deciding registering backlight
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Origin: https://git.kernel.org/linus/dce4ec2e452fddb7542b5fc15d0e6b8531f6d5eb
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The ASUS K53SM's ACPI table queries _OSI("Windows 2012") in the video
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output device's _BCL and _BCM control method instead of the usual _INI
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functions of the _SB or PCI host bridge PCI0 devices. This made our
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video module thought this is a pre-Win8 system when deciding if we
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should register a backlight interface for it and the end result is that
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a non-working acpi_video interface is registered and user is unable to
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control backlight from GUI. Solve this problem by evaluating _BCL control
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method before doing the decision.
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Note that for some Thinkpad systems, the _BCL is also required to be
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evaluated for the hotkey event to be generated no matter if we will
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register an ACPI video backlight interface for it or not. Since the
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thinkpad_acpi module will do this anyway we didn't add such a thing in
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the video module previously. But now with this change here, the
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thinkpad_acpi module is no more necessary for those systems regarding
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backlight functionality.
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Link: https://bugzilla.kernel.org/show_bug.cgi?id=85051
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Reported-and-tested-by: Ralf Jung <post+kernel@ralfj.de>
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Signed-off-by: Aaron Lu <aaron.lu@intel.com>
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Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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---
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drivers/acpi/video.c | 15 +++++++++++++++
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1 file changed, 15 insertions(+)
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--- a/drivers/acpi/video.c
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+++ b/drivers/acpi/video.c
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@@ -1836,6 +1836,19 @@ static void acpi_video_dev_register_back
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printk(KERN_ERR PREFIX "Create sysfs link\n");
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}
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+static void acpi_video_run_bcl_for_osi(struct acpi_video_bus *video)
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+{
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+ struct acpi_video_device *dev;
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+ union acpi_object *levels;
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+
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+ mutex_lock(&video->device_list_lock);
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+ list_for_each_entry(dev, &video->video_device_list, entry) {
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+ if (!acpi_video_device_lcd_query_levels(dev, &levels))
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+ kfree(levels);
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+ }
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+ mutex_unlock(&video->device_list_lock);
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+}
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+
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static int acpi_video_bus_register_backlight(struct acpi_video_bus *video)
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{
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struct acpi_video_device *dev;
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@@ -1843,6 +1856,8 @@ static int acpi_video_bus_register_backl
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if (video->backlight_registered)
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return 0;
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+ acpi_video_run_bcl_for_osi(video);
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+
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if (!acpi_video_verify_backlight_support())
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return 0;
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