On Tue, 2007-08-14 at 19:58 +0800, Richard Hughes wrote:
>
> On Wed, 2007-08-08 at 14:37 +0800, Zhang Rui wrote:
> > On Mon, 2007-07-30 at 12:47 +0100, Richard Hughes wrote:
> > > On 30/07/07, Matthew Garrett <mjg59@xxxxxxxxxxxxx> wrote:
> > > > On Sun, Jul 29, 2007 at 12:40:16PM -0400, Luming Yu wrote:
> > > > > switch (event) {
> > > > > case ACPI_VIDEO_NOTIFY_SWITCH: /* User requested a
> switch,
> > > > > * most likely via
> hotkey. */
> > > > > acpi_bus_generate_event(device, event, 0);
> > > > > + keycode = KEY_UNKNOWN;
> > > >
> > > > KEY_SWITCHVIDEOMODE ?
> > >
> > > Yes, please use this. This is what other ACPI drivers are using.
> > >
> > > > What's wrong with the existing KEY_BRIGHTNESSDOWN and
> KEY_BRIGHTNESSUP?
> > >
> > > Agree, this matches other drivers like thinkpad_acpi and
> sony-laptop.
> > >
> > > > > +#define KEY_BRIGHTNESS_ZERO 0x1fd
> > > > > +#define KEY_BRIGHTNESS_OFF 0x1fe
> > > >
> > > > You almost certainly want to go via linux-input if you're adding
> new
> > > > keycodes.
> > >
> > > Yup - do we have to distinguish between zero and off? Or is off
> > > "switch panel backlight off" and zero is "switch to lowest
> brightness
> > > level"?
> > >
> > Hmm, I think they are slightly different.
> > IMO, "zero" equals _BCM(0), it means to turn off the backlight, but
> we
> > may still see the screen if there is a ambient light.
> > "off" means turn off the output device, i.e. set to D1/D2/D3 state.
>
> Sure, so they are different states, but to a user they are both
> effectively the same "screen is off". Is there any use case to
I'm not sure of this.
But in some cases, I do can still see the screen although it's very dark
after I "echo 0 >/sys/class/backlight/acpi_video0/brightness".
IMO, this is because the ambient light is on.
Thanks,
Rui
> removing the backlight without powering down the display?
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