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SubjectRe: [PATCH] Add backlight driver for Nvidia-based Apple Macbook Pros
On Sat, 7 Jun 2008 03:54:36 +0100 Matthew Garrett <mjg59@srcf.ucam.org> wrote:

> Nvidia-based Apple Macbook Pros don't appear to handle backlight control
> through the graphics card registers or ACPI, but instead trigger changes
> via SMI calls. This driver registers a generic backlight device that
> lets existing userspace deal with it. Code derived from Julien Blache's
> Pommed application.
>
> Signed-off-by: Matthew Garrett <mjg@redhat.com>
>
> ...
>
> --- /dev/null
> +++ b/drivers/video/backlight/mbp_nvidia_bl.c
> @@ -0,0 +1,114 @@
> +/*
> + * Backlight Driver for Nvidia 8600 in Macbook Pro
> + *
> + * Copyright (c) Red Hat <mjg@redhat.com>
> + * Based on code from Pommed:
> + * Copyright (C) 2006 Nicolas Boichat <nicolas @boichat.ch>
> + * Copyright (C) 2006 Felipe Alfaro Solana <felipe_alfaro @linuxmail.org>
> + * Copyright (C) 2007 Julien BLACHE <jb@jblache.org>

Did this patch have appropriate attribution and signoffs?

> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This driver triggers SMIs which cause the firmware to change the
> + * backlight brightness. This is icky in many ways, but it's impractical to
> + * get at the firmware code in order to figure out what it's actually doing.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/platform_device.h>
> +#include <linux/backlight.h>
> +#include <linux/err.h>
> +#include <linux/dmi.h>
> +#include <linux/io.h>
> +
> +struct backlight_device *mbp_backlight_device;
> +
> +static struct dmi_system_id __initdata mbp_device_table[] = {
> + {
> + .ident = "3,1",
> + .matches = {
> + DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro3,1"),
> + },
> + },
> + {
> + .ident = "3,2",
> + .matches = {
> + DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro3,2"),
> + },
> + },
> + {
> + .ident = "4,1",
> + .matches = {
> + DMI_MATCH(DMI_SYS_VENDOR, "Apple Inc."),
> + DMI_MATCH(DMI_PRODUCT_NAME, "MacBookPro4,1"),
> + },
> + },
> + { }
> +};
> +
> +static int mbp_send_intensity(struct backlight_device *bd)
> +{
> + int intensity = bd->props.brightness;
> +
> + outb(0x04 | (intensity << 4), 0xb3);
> + outb(0xbf, 0xb2);
> +
> + return 0;
> +}
> +
> +static int mbp_get_intensity(struct backlight_device *bd)
> +{
> + outb(0x03, 0xb3);
> + outb(0xbf, 0xb2);
> + return inb(0xb3) >> 4;
> +}
> +
> +static struct backlight_ops mbp_ops = {
> + .get_brightness = mbp_get_intensity,
> + .update_status = mbp_send_intensity,
> +};
> +
> +static int __init mbp_init(void)
> +{
> + if (!dmi_check_system(mbp_device_table))
> + return -ENODEV;
> +
> + if (!request_region(0xb2, 2, "Macbook Pro backlight"))
> + return -ENXIO;
> +
> + mbp_backlight_device = backlight_device_register("mbp_backlight",
> + NULL, NULL,
> + &mbp_ops);
> + if (IS_ERR(mbp_backlight_device))
> + return PTR_ERR(mbp_backlight_device);

Missing release_region()?

> + mbp_backlight_device->props.max_brightness = 15;
> + mbp_backlight_device->props.brightness =
> + mbp_get_intensity(mbp_backlight_device);
> + backlight_update_status(mbp_backlight_device);
> +
> + return 0;
> +}
> +
> +static void __exit mbp_exit(void)
> +{
> + backlight_device_unregister(mbp_backlight_device);
> +
> + release_region(0xb2, 2);
> +}
> +
> +module_init(mbp_init);
> +module_exit(mbp_exit);
> +
> +MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
> +MODULE_DESCRIPTION("Nvidia-based Macbook Pro Backlight Driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("dmi:*:svnApple Inc.:pnMacBookPro3,1:*");
> +MODULE_ALIAS("dmi:*:svnApple Inc.:pnMacBookPro3,2:*");
> +MODULE_ALIAS("dmi:*:svnApple Inc.:pnMacBookPro4,1:*");



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