Hi Pradeep,
I think the following command doesn't work to you:
echo 5 > /sys/class/backlight/acpi_video0/brightness
It the above command not work, that means EC didn't change backlight
value:
Method (_BCM, 1, NotSerialized)
{
Divide (Arg0, 0x0A, Local0, Local1)
Decrement (Local1)
Store (Local1, ^^^^LPC.EC0.BRTS) <=== write backlight value to EC register
}
Per my understood, EC firmware should change brightness but didn't do that, another
way is touch i915 register in _BCM.
Acer machine provide a broken _BCM implementation and they didn't test it.
Thanks a lot!
Joey Lee
於 二，2012-03-13 於 09:12 -0400，Pradeep Subrahmanion 提到：
> Hi Joey,
>
> yes , /sys/class/backlight/intel_backlight exists . I tried giving
> acpi_backlight=vendor in grub config.Hot keys works like earlier.But
> increasing brightness after maximum levels give blank screen(like
> earlier).
>
> I have attached acpidump.
>
> ----
> Thanks ,
>
> Pradeep Subrahmanion
>
> On Tue, 2012-03-13 at 11:10 +0800, joeyli wrote:
> > Hi Pradeep,
> >
> > 於 日，2012-03-11 於 19:42 +0000，Florian Tobias Schandinat 提到：
> > > Hi,
> > >
> > > On 03/11/2012 06:21 PM, Pradeep Subrahmanion wrote:
> > > > Hi ,
> > > >
> > > > Brightness control was not working on Acer Aspire 4736 using
> > > > default ACPI interface. acer-acpi also do not support 4730 series since
> > > > it uses new WMI interface.
> > > > This driver adds brightness control by accessing the LBB PCI
> > > > configuration register. This approach may also work on other laptops in
> > > > 4730 series .But currently , it is only tested for
> > > > Aspire 4736.
> > > >
> >
> > Pleae check does there have following interface?
> >
> > /sys/class/backlight/intel_backlight
> >
> > And,
> > did you try kernel parameter "acpi_backlight=vendor", does it work to
> > you?
> >
> > Please attach acpidump: acpidump > acpidump.dat
> >
> >
> > Thanks
> > Joey Lee
> >
> > > > From 893031c1e9bdefd9642b98825062b5df98af0d77 Mon Sep 17 00:00:00 2001
> > > > From: Pradeep Subrahmanion <subrahmanion.pradeep@xxxxxxxxx
> > > > <mailto:subrahmanion.pradeep@xxxxxxxxx>>
> > > > Date: Sun, 11 Mar 2012 23:11:23 -0400
> > > > Subject: [PATCH] Added backlight driver for Acer Aspire 4736
> > > >
> > >
> > > the commit message should be here, I think.
> > >
> > > >
> > > > Signed-off-by: Pradeep Subrahmanion <subrahmanion.pradeep@xxxxxxxxx
> > > > <mailto:subrahmanion.pradeep@xxxxxxxxx>>
> > >
> > > Please resend this email in the correct format: As you can see in my
> > > email the text version of your patch is severely screwed up and nobody
> > > wants to even try converting a HTML format to a proper patch again,
> > > probably most people won't even receive an email that has a HTML part as
> > > their spam filter are going to handle it as spam. git send-email will
> > > take care of it for you if you configure it for your account.
> > > You should also cc Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> as he's the
> > > one who handles backlight patches at the moment.
> > >
> > >
> > > Best regards,
> > >
> > > Florian Tobias Schandinat
> > >
> > > > ---
> > > > drivers/video/backlight/acer4736_bl.c | 110
> > > > +++++++++++++++++++++++++++++++++
> > > > 1 files changed, 110 insertions(+), 0 deletions(-)
> > > > create mode 100644 drivers/video/backlight/acer4736_bl.c
> > > >
> > > > diff --git a/drivers/video/backlight/acer4736_bl.c
> > > > b/drivers/video/backlight/acer4736_bl.c
> > > > new file mode 100644
> > > > index 0000000..6fe2937
> > > > --- /dev/null
> > > > +++ b/drivers/video/backlight/acer4736_bl.c
> > > > @@ -0,0 +1,110 @@
> > > > +/*
> > > > + * Backlight driver for Acer Aspire 4736
> > > > + *
> > > > + * Copyright (C) Pradeep Subrahmanion <subrahmanion.pradeep@xxxxxxxxx
> > > > <mailto:subrahmanion.pradeep@xxxxxxxxx>>
> > > > + *
> > > > + * 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 uses LBB PCI configuration register to change the
> > > > + * backlight brightness.
> > > > + *
> > > > + */
> > > > +
> > > > +#include <linux/module.h>
> > > > +#include <linux/kernel.h>
> > > > +#include <linux/init.h>
> > > > +#include <linux/backlight.h>
> > > > +#include <linux/err.h>
> > > > +#include <linux/dmi.h>
> > > > +#include <linux/io.h>
> > > > +#include <linux/pci.h>
> > > > +
> > > > +static u8 max_brightness = 0xFF;
> > > > +static u8 lbb_offset = 0xF4;
> > > > +static unsigned int device_id = 0x2a42;
> > > > +static unsigned int vendor_id = 0x8086;
> > > > +
> > > > +struct backlight_device *acer_backlight_device;
> > > > +struct pci_dev *pdev;
> > > > +
> > > > +static int acer_dmi_match(const struct dmi_system_id *id)
> > > > +{
> > > > + printk(KERN_INFO "acer4736_bl: %s detected\n", id->ident);
> > > > + return 1;
> > > > +}
> > > > +
> > > > +static const struct dmi_system_id __initdata acer_device_table[] = {
> > > > +{
> > > > + .callback = acer_dmi_match,
> > > > + .ident = "Aspire 4736",
> > > > + .matches = {
> > > > + DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
> > > > + DMI_MATCH(DMI_PRODUCT_NAME, "Aspire 4736"),
> > > > + },
> > > > + },
> > > > + {}
> > > > +};
> > > > +static int read_brightness(struct backlight_device *bd)
> > > > +{
> > > > + u8 result;
> > > > + pci_read_config_byte(pdev, lbb_offset, &result);
> > > > + return result;
> > > > +}
> > > > +
> > > > +static int update_brightness(struct backlight_device *bd)
> > > > +{
> > > > + u8 intensity = bd->props.brightness;
> > > > + if (intensity > max_brightness) {
> > > > + printk(KERN_INFO "Acer4736_bl: Invalid parameter. Maximum value is %d"
> > > > + , max_brightness);
> > > > + return -1;
> > > > + }
> > > > + pci_write_config_byte(pdev, lbb_offset, intensity);
> > > > + return 0;
> > > > +}
> > > > +static const struct backlight_ops acer_backlight_ops = {
> > > > + .get_brightness = read_brightness,
> > > > + .update_status = update_brightness,
> > > > +};
> > > > +
> > > > +static int __init acer4736_bl_init(void)
> > > > +{
> > > > + struct backlight_properties props;
> > > > + if (!dmi_check_system(acer_device_table))
> > > > + return -ENODEV;
> > > > +
> > > > + pdev = pci_get_device(vendor_id, device_id, NULL);
> > > > +
> > > > + if (!pdev)
> > > > + return -ENODEV;
> > > > +
> > > > + printk(KERN_INFO "Loading Acer 4736 backlight driver\n");
> > > > + memset(&props, 0, sizeof(struct backlight_properties));
> > > > + props.type = BACKLIGHT_RAW;
> > > > + props.max_brightness = max_brightness;
> > > > +
> > > > + acer_backlight_device = backlight_device_register("acer_backlight",
> > > > + NULL, NULL, &acer_backlight_ops, &props);
> > > > + acer_backlight_device->props.max_brightness = max_brightness;
> > > > + acer_backlight_device->props.brightness =
> > > > + read_brightness(acer_backlight_device);
> > > > + backlight_update_status(acer_backlight_device);
> > > > +
> > > > + return 0;
> > > > +}
> > > > +
> > > > +static void __exit acer4736_bl_exit(void)
> > > > +{
> > > > + pci_dev_put(pdev);
> > > > + backlight_device_unregister(acer_backlight_device);
> > > > +}
> > > > +
> > > > +module_init(acer4736_bl_init);
> > > > +module_exit(acer4736_bl_exit);
> > > > +
> > > > +MODULE_AUTHOR("Pradeep Subrahmanion <subrahmanion.pradeep@xxxxxxxxx
> > > > <mailto:subrahmanion.pradeep@xxxxxxxxx>>");
> > > > +MODULE_DESCRIPTION("Acer Aspire 4736 Backlight Driver");
> > > > +MODULE_LICENSE("GPL");
> > > > +MODULE_DEVICE_TABLE(dmi, acer_device_table);
> > > > --
> > > > 1.7.2.5
> > > >
> > > > -------------
> > > >
> > > > Pradeep Subrahmanion
> > >
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > > the body of a message to majordomo@xxxxxxxxxxxxxxx
> > > More majordomo info at http://vger.kernel.org/majordomo-info.html
> > > Please read the FAQ at http://www.tux.org/lkml/
> > >
> >
> >
>
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