On Wed, 2008-12-31 at 10:58 +0800, Zhang Rui wrote:
> On Wed, 2008-12-31 at 10:01 +0800, Matthew Garrett wrote:
> > On Wed, Dec 31, 2008 at 09:43:01AM +0800, Zhang Rui wrote:
> >
> > > then how about this case:
> > > 1. set the brightness level to 5 via sysfs I/F
> > > 2. set the backlight to another level via HOTKEYS.
> > > 3. setting it back to 5 doesn't work because bd->props.brightness
> > > is still 5.
> >
> > If they're using the ACPI interface then video.c should update
> > props.brightness itself.
> >
> > > IMO, the real problem is that bd->props.brightness doesn't reflect the
> > > actual brightness.
> >
> > If you want the actual brightness, why aren't you reading
> > actual_brightness?
> >
> right, that's the problem.
> because IMO, we don't need the actual_brightness any more. :)
> And if you agree that bd->props.brightness doesn't reflect the actual
> brightness, we can see that
> if (bd->props.brightness != brightness) {
> bd->props.brightness = brightness;
> backlight_update_status(bd);
> }
> doesn't make sense because "bd->props.brightness != brightness" doesn't
> mean anything.
>
> But if bd->props.brightness does reflect the actual brightness, then do
> we need "actual_brightness" any more?
>
>
> > If they're using the ACPI interface then video.c should update
> > props.brightness itself.
> that also makes sense, patch attached.
> But anyway, we still need some changes in the video backlight class.
> right?
>
> From: Zhang Rui <rui.zhang@xxxxxxxxx>
> Subject: always update props.brightness when brightness is changed
>
> always update pros.brightness no matter the backlight is changed
> via procfs, hotkeys or sysfs.
by the way, with this patch applied, we really don't need
"actual_brightness" any more, at least for ACPI backlight class I/F.
is there any chance that "actual_brightness" returns a different value
from "brightness"?
thanks,
rui
>
> Sighed-off-by: Zhang Rui <rui.zhang@xxxxxxxxx>
> ---
> drivers/acpi/video.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> Index: linux-2.6/drivers/acpi/video.c
> ===================================================================
> --- linux-2.6.orig/drivers/acpi/video.c
> +++ linux-2.6/drivers/acpi/video.c
> @@ -481,6 +481,7 @@ acpi_video_device_lcd_set_level(struct a
> int status = AE_OK;
> union acpi_object arg0 = { ACPI_TYPE_INTEGER };
> struct acpi_object_list args = { 1, &arg0 };
> + int state;
>
>
> arg0.integer.value = level;
> @@ -489,6 +490,10 @@ acpi_video_device_lcd_set_level(struct a
> status = acpi_evaluate_object(device->dev->handle, "_BCM",
> &args, NULL);
> device->brightness->curr = level;
> + for (state = 2; state < device->brightness->count; state++)
> + if (level == device->brightness->levels[state])
> + device->backlight->props.brightness = state - 2;
> +
> return status;
> }
>
>
>
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